
I KB I lliill 



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MODEL ENGINE CONSTRUCTION. 



Second Edition. Revised. 

BRITISH LOCOMOTIVES : their History, Construc- 
tion, and Modern Development. By C. J. Bowen 
Cooke, Assistant, London and North- Western Loco- 
motive Department. With 150 Illustrations. Crown 
8vo. 7s. 6d. 

" An excellent work. ... A very valuable addition to technical 
railway literature. It ought to be in the library of every one con- 
cerned with railways or interested in them. Every driver and fireman 
should possess a copy. It supplies a distinct want, and will, we have 
no doubt, be in large demand in all parts of the world." — Engineer. 

"We congratulate the author on having produced a book which 
will be deservedly successful." — Railway Engineer. 



By the late Sir George Findlay, Assoc. Inst. C.E., 

Manager of the London and North -Western 

Railway. 

THE "WORKING AND MANAGEMENT OF AN 
ENGLISH RAILWAY. Fifth Edition, thoroughly 
revised and enlarged. With Biography and Portrait 
of Sir George Findlay, Appendix, and numerous 
Illustrations. Crown 8vo. Cloth. Is. Qd. 

" This is a delightful book." — Engineer. 

" A very interesting work throughout." — Eailway Engineer. 



Works by a Foreman Pattern Makkr. 

PRINCIPLES OF PATTERN MAKING. 3s. 6d. 
PRINCIPLES OF FITTING. 5s. 
IRONFOUNDING. Second Edition. 4s. 
METAL TURNING. 4s. 



LONDON: WHITTAKER & CO., PATERNOSTER SQUARE. 



MODEL ENGINE CONSTRUCTION 

"WITH PRACTICAL INSTRUCTIONS. 

TO ARTIFICERS AND AMATEURS. 



• 



J. ALEXANDER 



CONTAINING 

NUMEEOUS ILLUSTRATIONS AND TWENTY-ONE WORKING 

DRAWINGS FROM ORIGINAL DRAWINGS BY THE 

AUTHOR, AND RE-DRAWN BY C. E. JONES. 



• > i - . 






WHITTAKER AND CO., 

2, WHITE HART ST., PATERNOSTER SQUARE, LONDON, 
and 66, Fifth Avenue, New York. 

1894. 

[All rights reserved.] 



3 CQ <? 3 



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8, 






T"3 ^o 



3 



Richard Clay & Sons, Limited, 
London & Bungay. 



• • • • 

• • • 



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■ •• w • • •( 




PREFACE. 



Having had some experience in the construction 
of model steam-engines, I publish this work for the 
purpose of giving a few practical instructions to 
Artificers, but more especially to Amateurs who 
wish to make a working model steam-engine, 
provided they be supplied with the proper tools, 
and only know how to set about it. I commence 
by enumerating the necessary tools, giving the 
average price of a few of them, take up the 
boilers and their fittings, with engine details, show 
how to work up the separate parts from their 
castings, fit these together, and erect a horizontal 
engine and test it under steam. All this is min- 
utely described, as it forms the groundwork for the 
construction of all the other engines. I next 
give examples of the different types of engines, 
Stationary, Locomotive, and Marine, as well as how 
to make a carriage and a model railway. After 
giving a few notes on pattern-making, proportions 
of engines, property of steam, etc., I conclude with 



vi PREFACE. 

a hot-air engine, which is easily fitted up. I have 
omitted oscillating cylinder engines, such as are 
sold in large numbers in the shops of the model- 
makers for boys to play with, as these are really 
models of no existing type of engine, merely toys ; 
the making of them serves no educational purpose, 
and when made they are not at all satisfactory as 
regards their steaming powers. All the engines 
here have double-acting fixed slide-valve cylinders, 
and approximate in construction to those in actual 
practice. If carefully made according to instructions, 
none of them will fail to work, and it would be 
possible to demonstrate the action of the steam- 
engine to a class from any one of them, which 
really makes a model engine of some use after being 
made, as well as a source of pleasure to the maker. 

The locomotive boiler described on page 37 will 
raise plenty of steam, as it maintains a good draught 
of air through the fire-box and fire-tube when at 
work. I have omitted the marine engine (as made 
at the present day) with circulating-pumps, air- 
pumps, and surface condenser, as being too com- 
plicated, but give two different types of compound 
non-condensing engines, which will afford some 
scope for the amateur's ability. 

As regards the working drawings, these have all 
been carefully re-drawn by a competent draughts- 
man from original sketches drawn by me. Four of 



PREFACE. vii 

the sheets contain drawings of engines designed 
and constructed by myself, viz. the locomotive 
and tender, the bogie-tank locomotive, the centre 
crank horizontal, and the traction engines. 

All these drawings may be thoroughly relied upon 
as being correct, and in one or two instances, by 
doubling the dimensions over all, a larger and more 
powerful working engine can be made. 

Certain people maintain that model engine-making, 
like some other " hobbies," is simply a waste of time, 
and nothing more. Such persons, I am sure, are 
ignorant of what they are talking about, and I feel 
certain that most of my readers will agree with 
me "that there are few pastimes better fitted to 
give such good training to the mind, the eye, and 
the hand at one and the same time as model- 
making." For young Mechanical Engineers, during 
their apprenticeship, it is invaluable. All who can 
afford it should have a small workshop of their 
own, fitted with a set of tools, including a good 
lathe, so that they can devote their spare time to 
this pastime. For the same class who cannot afford 
to erect a workshop and procure tools, it might be 
advantageous if the Heads of large engineering 
establishments were to allow their apprentices and 
young engineers the use of the tools in the workshop 
(subject to certain regulations) during evenings and 
spare hours, for them to keep their hands in by 



viii PREFACE. 

making small engines, and perhaps supplement this 
by giving prizes for the best constructed and the 
best working engine under steam, made by their 
apprentices. By so doing, many lads would be kept 
out of mischief and temptation, be encouraged to 
follow their profession or trade, become dexterous 
in the use of different kinds of tools, get intimately 
acquainted with the mechanism of the several parts 
of the steam-engine, and acquire knowledge that 
would not be easily forgotten, and which would be 
of great service during after-life. 

It has been suggested to me that if a Postal 
Amateur Mechanics' Society was started, on the 
same lines as the Postal Photographic Society, for 
the interchange of patterns, ideas, etc., between 
amateurs living at a distance from the large centres, 
such society would bring persons of kindred tastes 
into communication with each other. 

J. A. 



CONTENTS. 



PART I. 

BOILER AND ENGINE DETAILS, WITH TOOLS. 

CHAP. PAGR 

I. TOOLS USED IN MODEL ENGINE-MAKING ... 3 

II. THE BOILERS AND THEIR FITTINGS ... ... 31 

III. THE STEAM-ENGINE ... ... ... ... 78 

IV. FITTING UP THE ENGINE, ETC. ... ... 124 

V. REVERSING-GEAR ... ... ... ... 133 

PART II. 

DIFFERENT TYPES OF ENGINES: STATIONARY, 
LOCOMOTIVE, MARINE. 

VI. BEAM, HORIZONTAL, AND VERTICAL ENGINES 157 
VII. TRACTION, PORTABLE, AND SEMI-PORTABLE 

ENGINES ... ... ... ... ... 168 

VIII. LOCOMOTIVE ENGINE AND TENDER ... ... 200 

IX. LOCOMOTIVE ENGINES ... ... ... 231 

X. CARRIAGES AND RAILWAYS ... ... ... 253 

XI. COMPOUND MARINE ENGINES... ... ... 281 

XII. PROPORTIONS OF ENGINES, ETC., PATTERN- 
MAKING, CASTINGS, ETC. ... ... ... 296 

XIII. HOT-AIR ENGINE, SMALL POWER ENGINE, AND 

NOTES ... ... ... ... ... 310 



LIST OF ILLUSTRATIONS. 



FIG. 


PAGE 


FIG. 


1. Bench lathe ... 


5 


34. 


2. Driver-cbuck ... 


8 




3. Wood-chuck 


9 


35. 


4. Drill-chuck 


10 




5. Lathe-carrier ... 


10 


36. 


6. Bell-chuck 


11 


37. 


7. Lathe-dog 


11 




8. Face-plate 


12 


38. 


9. Chisels for turning . . . 


15 




10. Soldering bolts 


23 


39. 


11a. Boiler for kitchen 




40. 


fire ... 


32 


41. 


11b. Safety - valve with 




42. 


weight 


52 




12. Spring safety-valve ... 


55 


43. 


13. Direct - acting spring- 






valve 


56 


44. 


14, 15. Pressure-gauge 


57 




16. Water-gauge 


62 


45. 


17. ,, simpler ... 


64 


46. 


18. Gauge-cock 


65 


47. 


19. Whistle 


66 


48. 


20. Simple whistle 


68 




21. Clack-valve ... 


69 


49. 


22. Wheel- valve 


70 


50. 


23. Pump 


72 


51. 


24. Injector 


75 




25. The cylinder 


79 


52. 


26. Cylinder valve face ... 


82 




27. Cover for chucking in 




53. 


lathe 


85 




28. Stuffing-box and gland 


86 


54. 


29. Piston with ring sur- 




55. 


rounding it ... 


94 


56. 


30. Connecting-rod 


98 


57. 


31. Bearings and plurn- 






mer- block 


100 


58. 


32. Standard for vertical 






engine 


-102 


59. 


33. Crank-axle 


103 





Crank-axle with centre 
crank ... ... 105 

The slide - valve, and 

section of steam-chest 107 
The eccentric-strap ... Ill 
The eccentric - pulley 

and strap finished ... 112 
Sheet-brass eccentric- 
strap ... ... 118 

Throttling-governor ... 119 

Loose eccentric ... 135 

,, ,, plan ... 135 

The ordinary link 

motion ... ... 137 

The slot-link marked 

out on a piece of metal 140 
The slot-link after be- 
ing finished ... ... 141 

Lifting- links ... ... 142 

Expansion-valve ... 145 
Joy's valve-gear ... 153 

Action of steam in the 

cylinder, &c. facing 154 
Beam engine ... ... 158 

The ' ' Parallel Motion " 159 
Perspective view of 

traction engine ... 169 
Perspective view of 

portable engine ... 190 
Perspective view of 

underneath engine ... 195 
Bogie-tank locomotive 232 

The train 252 

Railway, elevation of . . . 268 
Railway, transverse 
section of ... ... 268 

Patterns for making a 

cylinder 303 

Elevation and plan of 
pattern for chairs ... 307 



LIST OF WORKING DRAWING SHEETS. 



Locomotive boiler , 


.. Sheet No. 


1 


Vertical boiler 


5) 


55 


2 


Beam engine 


,, 


55 


3 


Horizontal engine ... 


55 


55 


4 


,, j, 


1) 


55 


5 


Vertical engine 


)) 


55 


6 


Inverted vertical engine ... 


5» 


55 


7 


Traction engine 


)> 


55 


8(A) 


j, ,, 


,, 


55 


8(B) 


,, ,, ... 


,, 


55 


8(C) 


Portable engine 


)> 


55 


9 


Semi-portable engine 


,, 


55 


10 


Locomotive engine and tender ... 


i) 


55 


11(A) 


55 55 55 55 "• ••• 


>> 


55 


11(B) 


5> 5J 55 )> 


)) 


55 


11(C) 


Bogie-tank locomotive 


•• )) 


55 


12 


Single locomotive 


•• J5 


55 


13 


Six-coupled tank locomotive 


55 


55 


14 


Eail way carriage ... 


55 


55 


15 


Railway wagon and van ... 


55 


55 


16 


Railway 


55 


55 


17 


Railway signal 


55 


55 


18 


Compound marine engine 


55 


55 


19 


Compound tandem engine 


•• 55 


55 


20 


Hot-air engine 


... ,, 


55 


21 


The above are also published in a sep 


%r ale form 







PART I. 

BOILER AND ENGINE DETAILS, WITH 

TOOLS. 



B 



MODEL ENGINE CONSTRUCTION. 



CHAPTER I. 

TOOLS REQUIRED IN MODEL ENGINE-MAKING. 

The lathe is an indispensable tool, and cannot be 
done without ; but it requires some little practice 
to be able to use it properly. Let the amateur 
purchase a 3 J" centre bench lathe from any of the 
makers, but without back gear, as very often this 
is not used. The price varies, but we think that 
a good one may be had from £3 10s. up to £6, 
according to finish, and the number of chucks, etc. 
that go with it. Along with each lathe is usually 
supplied a drill- and driver-chuck, a hand-rest, and 
two tees. A face-plate and slide-rest are extras, 
and must be ordered if required, though we propose 



4 MODEL ENGINE CONSTRUCTION. 

to do without them here. A 3J" centre lathe is a 
suitable size to purchase, as it is fairly strong, and 
will turn tolerably heavy work, and fine work quite 
as well, i. e. if the lathe is well made, the centres 
truly in line, and properly hardened, so as not to 
wear away rapidly. A lathe (Fig. 1) consists of two 
supports, firmly connected at their base, and fastened 
at right angles to the iron bed (which is 30" long, 
and planed quite true along the top) by means of 
screws, A. The outer poppet-head is bored for the 
screw, and the inner one is fitted with a collar, within 
which the mandrel that carries the speed pulleys 
turns ; the left end of the mandrel is concave, so as 
to allow of the steel point of the screw being 
tightened up and fit closely. C is called a T-rest ; 
this slides along the slot in the bed, and can be 
clamped at any point, as well as elevated or de- 
pressed, when required. This is used for leaning 
the cutting tool upon, in order to afford greater 
steadiness when working. B is the right-hand 
poppet-head or tail-stock, which is also movable 
along the slot in the bed, and capable of being 
fastened anywhere, to suit the length of work 




Fig. 1. — Bench Lathe. 

A, outer poppet-head and speed pulleys ; B, tail-stock or 
live-head ; C, T-rest ; D, crank-axle and fly-wheel j 
E, treadle ; F, gut-band. 



TOOLS USED IN MODEL ENGINE-MAKING. 7 

between the centres ; its point can. be advanced or 
drawn back, as required, by means of the screw and 
hand- wheel. D is the crank-axle which is connected 
with the treadle E by means of a rod, and so turns 
the fly-wheel, and this by means of a chain, or 
gut-band F, connects with the speed pulleys com- 
municating motion to the mandrel. The pulleys 
on the spindle and mandrel are three or four in 
number, of different sizes, and so arranged that 
when the band is placed on the left-hand pulley 
a very rapid motion is given to the mandrel, as 
when turning wood. This motion is reduced more 
and more as the band is transferred to the right, 
till, at the extreme right, the rotatory motion is 
much slower than that of the spindle, and is used 
for iron-turning. There is generally a three-speed 
fly-wheel on the driving-axle as well. When the 
lathe is used for turning, and work must be centred 
in it, certain contrivances made of iron called 
" chucks " are fixed to the mandrel on which the 
speed pulleys are placed, and are for the purpose 
of centering the work, and making it revolve when 
the lathe is driven. Castings for making lathes 



8 MODEL ENGINE CONSTRUCTION. 

are sold, but we advise the amateur to purchase 
his lathe ready made, for unless this tool is well 
made, with a perfectly flat bed, the points properly 
hardened, and standing in line facing each other, 
it will never turn out good work, even with the 
most experienced workman. 

For metal-turning, a driver-chuck is used. This 
screws by one end on to the mandrel, and carries 




Fig. 2. 

a steel centre-point at the other ; a steel rod which 
is generally bent at right angles outside, so as to 
be parallel to the line of centres, passes through 
the bore of the mandrel, and is fixed in position by 
a set-screw. Against this rod, the shank of the 
lathe-carrier (attached to the work) rests, and is 
taken round with it when the lathe revolves (see 
Kg. 2). 

A wood-chuck is similar to the above, but carries 



TOOLS USED IN MODEL ENGINE-MAKING. 9 

a three-pronged fork at one end. This is held in 
the chuck with a set-screw, the fork can be driven 
tightly into a piece of wood before placing it in the 
lathe ; the prongs grip the wood, when the movable 
head is screwed up tight, and cause it to revolve 
with the lathe (see Fig. 3). 

A drill-chuck is much the same as the last, 
having a hole at one end with a set-screw into which 




Fig. 3. 

different-sized drills can be inserted; some chucks 
have an extra plug for taking very fine drills. The 
wood-chuck can be made to act as a drill-chuck, 
by removing the fork, inserting the stem of a drill 
instead, and tightening it up with the set-screw 
(see Fig. 4). 

Lathe-carriers are made of steel or iron ; the head 
has a slot into which work must be firmly driven 
after centering, and tightened up by the set-screw. 
The stem, when the work is in the lathe, rests 



10 MODEL ENGINE CONSTRUCTION. 

against the crank of the driver-chuck, and revolves, 
taking the work round with it. It is best to have 
two or three different sizes of lathe-carriers, and 
any blacksmith will make them (see Fig. 5). 

A bell-chuck (see Fig. 6) is necessary for centering 
work to be drilled, as when boring out a cylinder. 
It is screwed on to the lathe, and the work, having 
been previously centre-punched, is put in the lathe, 
and retained in position by means of half-a-dozen 




Figs. 4, 5. 

set-screws, which are tightened up equally all round 
the work, so as to keep its centres in line with 
those of the lathe. The advantage of this tool is 
that, having a bell shape, the drill can be sent 
completely through the work and out at the other 
end, which cannot be done so well with a face-plate. 
The accurate centering of work in a bell-chuck is 
very difficult, and takes some practice to do it 
properly. Price 14s. to 30s. 



TOOLS USED IN MODEL ENGINE-MAKING. 11 

A lathe-dog is a contrivance which is useful for 
gripping fine work, and holding it in the lathe. 
The work is gripped between the two halves, the 




Fig. 6. 

screws serving to draw them together ; the tail can 
be bent, or left straight at one end to catch against 
the driver-chuck ; if bent, it can be passed through 
a hole in the face-plate when chucked (see Fig. 7). 




The slide-rest is a very expensive addition to 
a lathe (costing fully £3 for a 3^-" centre lathe), 
and we will dispense with it for our work; with 
a little practice it can readily be done without. 



12 



MODEL ENGINE CONSTRUCTION. 



A face-plate (Fig. 8) is a very useful adjunct to 
the lathe (costs 10s. to 15.5.). It is an iron disc, 
planed quite flat on one side, and screws on to the 
mandrel by the other. Slots radiate outwards from 
the centre; through these screws or clamps "lathe 
dogs," as they are called, pass, and by them work 
is clamped to the face-plate, and properly centred 
in the lathe. The face-plate revolves and carries 




Fig. 8. 



the work round with it, which should be so placed 
as to turn in line with the lathe-centres. Remove 
the steel point from the movable head, insert a suit- 
able sized drill. Feed the drill forwards, by gradually 
pushing it up against the work by turning the hand- 
wheel, and it will soon cut its way through, if kept 
from revolving. This is done by clamping to the 
drill-stem, at right angles, a small iron bar, forked, 
or with a ring at one end, through which the drill 



TOOLS USED IN MODEL ENGINE-MAKING. 13 

passes ; there is a set-screw for tightening up. The 
bar rests by its opposite end on the top of the 
T-rest, along which it slides with the drill. In this 
method, the work revolves and the drill "is station- 
ary, which gives the best results, but it is a little 
difficult to chuck the work properly at first. Work 
must always be first correctly centred, and then 
centre-punched, before attempting to chuck it in a 
lathe. 

A rose-cutter is useful for finishing a cylinder. 
After boring out the cylinder, while it is still chucked, 
fix this tool to the mandrel and feed by the hand- 
wheel. When it has gone through the cylinder, 
this latter will be found to be quite circular inside, 
and as smooth as glass. Different-sized cutters are 
required for different-sized cylinders. 

To drill a hole through a piece of brass. 

Besides the above method, we have found the 
following plan give satisfaction. In this method, 
the drill revolves and the work is kept stationary, 
and is used in all cases where a hole is required to 
be drilled through the metal, but the keeping exactly 
between the true centres is not of the same vital 



14 MODEL ENGINE CONSTRUCTION. 

importance as when boring-out a cylinder. Screw 
the wood-chuck on to the poppet-head, remove the 
fork, and insert a drill, punch a centre hole at both 
ends of the work before chucking, remove the point 
from the movable head, keep the work from revolv- 
ing, by gripping it with a pair of gas-fitters' pliers, 
or if larger, by clamping on a lathe-carrier, which 
will slide along the T-rest. Run the mandrel up 
against the work, and push the metal forwards on 
to the revolving drill by turning the hand-wheel. 
The drill will soon cut through the metal. The 
end of the work that rests against the mandrel 
must be filed flat before chucking, and be at right 
angles to the hole that is to be drilled. 

Note. — A 3 1" centre lathe will take the finest 
drills up to -J", for boring out brass or gun-metal. 

A set of wire-chucks, capable of taking various- 
sized drills, from T V up to -§-", will be found very 
useful, especially if they are self-centering. 

When turning metal, take care to chuck the 
work firmly ; it can then be turned down accurately 
to the required form (using a pair of callipers 
properly adjusted, to give the correct size in 



TOOLS USED IN MODEL ENGINE-MAKING. 15 

diameter) with a graver or steel chisel, and, finished 
with a fine file and oil, or emery cloth and oil, 
while still revolving in the lathe. 

After the metal is chucked, it is first "roughed 
down" with a graver to the required form; second, 
smoothed with a chisel ; third, polished with emery 
cloth and oil, and then removed from the lathe. 






Fig. 9. 



Be careful always when turning to use well- 
sharpened chisels; a grindstone is necessary to 
keep a good edge upon them. 

Chisels are of various shapes : some have a flat 
edge, others are bevelled, and others again taper to 
a sharp point at one end. Of the last variety, it 
is best to have a right, and left-hand tool. Chisels 
should be made of good square cast steel ; old files 



16 MODEL ENGINE CONSTRUCTION. 

do fairly well for this purpose — any blacksmith 
can make one out of an old file (see Fig. 9). 

A screw-cutting lathe is not required for our work, 
as all the screws we need can be made by hand, 
with a set of taps and a screw-plate. 

Vices. These are for holding metal when it is 
being filed down to lines previously marked upon 
it. We advise a 4" jaw vice for holding heavy work, 
and a small 2£" jaw table- vice for fine work, which 
can be attached to a bench or table. A small hand- 
vice, with a thumb-screw for tightening up the jaws, 
is very useful for gripping small work when filing. 
The small sizes range from 6s. up to 10s. 6d., and 
the larger sizes from £1 10s. up to £5. 

Files are sold in different shapes, and degrees of 
fineness in cut. A rasp is a very coarse file for 
roughing down wood ; " rough " files are used for 
shaping, — " bastard " files may be purchased of any 
shape, — " smooth," " dead smooths," the finest of 
all, complete the various forms, along with the 
"triangular" and "round" files. 

When using, fix the metal firmly in the vice, 
take the handle of the file in the right hand, 



TOOLS USED IN MODEL ENGINE-MAKING. 17 

press downwards with the left thumb on the tip 
of the file, pass it slowly and deliberately, but 
lightly, over the work, so as not to jump, and on 
the return stroke scarcely touch the work at all. 
The vice should be raised so high as to allow 
of the elbow passing over the vice when the arm 
is against the body, in order to use the file 
properly. 

Surface-plate. This is a very expensive article, 
and is a block of iron the surface of which is planed 
perfectly flat, and is used for grinding the faces 
of cylinders, slide valves, etc., by the aid of emery 
powder and oil. It can be done without, and an 
iron for ironing clothes used instead. Get a perfectly 
flat smoothing-iron, cut off the handle, and fix it 
upside-down in a block of wood, and on the flat sole 
of the iron grind all the cylinders, valves, etc. ; this 
does very well. Another way is to use a part of the 
flat bed of the lathe to grind the metal upon. The 
price of a surface-plate is from 8s. to 10s., according 
to size. 

Centre-punch. This is indispensable for metal- 
work, and consists of a piece of round steel tapering 

c 



18 MODEL ENGINE CONSTRUCTION. 

down to a point at one end, for marking out work, 
etc. ; price 10c?. 

Broaches or rimers are useful for enlarging circular 
apertures, as in cylinder covers. 

Screw-plate and taps. A watchmaker's plate and 
taps, from y 1 -^" to the finest sizes, are useful for 
delicate work. Another set of plate and taps, ^V' 
to yV'j is also required. These should be of the 
Whitworth Standard Gauge, and will be found quite 
sufficient for all our purposes. Prices run from 
3s. 6d. up to 7s. 6d. 

When it is desired to make a screw, take a piece 
of iron wire thicker than the size required, cut to 
the requisite length, leave a part longer than the 
full length of the screw for the head, grip the wire 
by one end in the hand-vice ; having separated the 
jaws of the large vice a little way, let the wire rest 
between the jaws, leaning on their upper surface ; 
take the hand-vice in the left hand and a file in 
the right hand, then gradually turn the hand-vice 
slowly round, keeping the wire resting on the upper 
surface of the vice ; file away, gradually passing round 
the wire, till it gets of a smaller diameter than the 



TOOLS USED IN MODEL ENGINE-MAKING. 19 

part held in the hand-vice — this part forms the head 
of the bolt. Continue filing until the stem is rather 
a tight fit in the hole of the screw-plate that is 
selected for use ; next grip the screw in the bench 
vice by the head ; take the screw-plate, oil the hole, 
and gradually force it on by turning from right to 
left, when it will be found that a screw-thread forms 
on the wire. If the screw-plate when turning feels a 
tight fit, it is best to unscrew it and file down the 
stem a little bit thinner, or it is apt to break in the 
screw-plate and give trouble. After the screw is 
made the requisite length, remove the bolt from the 
bench vice, then you can file the head square, and 
shorten it also. 

To make a nut, take a piece of brass, file it square, 
centre punch, fix in the vice, and with the hand- 
drill, drill a hole through it, suitable for the size 
of tap corresponding to the hole in the screw-plate 
that was used for making the thread on the bolt; 
grip the nut in the vice, and if a small tap, fix 
it in the hand-vice, oil it, and force it through 
the nut, while rotating the hand-vice in the right 
hand. This forms a thread in the nut of the same 






20 MODEL ENGINE CONSTRUCTION. 



size as that on the bolt. When done yon can file 
away the corners of the nnt and make it octagonal, 
if you choose. If properly made, the nnt will fit 
the screw on the little bolt. The above method 
applies to any size of bolt and nut it is desired to 
make ; but for taps of \" and larger sizes, instead 
of holding them in the hand-vice when using, tap 
wrenches with adjustable jaws, to suit different-sized 
taps (which give good leverage), are required to take 
them round ; brass wire is not good to make small- 
sized screws from, as the thread when made is very 
apt to give way or " strip," as it is called. A little 
practice will enable an amateur to make all the 
screws and nuts he requires. This plan we recom- 
mend, rather than buying them ready made. 

Pliers. It is best to have one or two pairs of 
different sizes, as well as a sharp cutting-edged pair 
for dividing wire, and a watchmaker's pair for deli- 
cate work. These cost about Is. 6d. each. 

Burnishers are highly-polished pieces of steel for 
polishing metal. They are rapidly moved over the 
part to be made bright ; a little weak beer facilitates 
this operation. 






TOOLS USED IN MODEL ENGINE-MAKING. 21 

A frame-saw is used for cutting metal, and is 
furnished with a thumb-screw to give varying 
degrees of rigidity, according to the nature of the 
work done. A good steel " tenon " saw does very 
well for cutting brass. Prices vary from 4s. to 
5s. 6d. Saws for the above cost from 6d. to lOd. 

Grindstone. A hand one is best for the amateur. 
Always use it with water, to prevent softening of 
the tool when sharpening chisels. These can be 
purchased. 15" x 2" is a suitable size. 

Oil-stones are required for sharpening the tools 
after grinding their edges. 

Iron block. A big block of iron, which can be 
firmly gripped in the bench vice, will be found 
useful for finishing off flat work, as bed -plates, 
locomotive frames, etc. Instead of this, an anvil 
would do. 

Callipers. A pair of these is required for getting 
the correct dimensions of work when turning ; those 
for outside measurement are the most useful. Price 
of a pair, about Is. 

Steel chisels, suitable for making steam-ports in 
small-sized engines, can be obtained at the model- 



22 MODEL ENGINE CONSTBUCTION. 

maker's, or made from a steel bar, 1|" long and 
T V' broad at cutting edge; this size is useful for 
fine work, but it is well also to have a larger size, 
at least 2" long and T V' wide at cutting edge. 

A pair of compasses with a set-screw are required, 
price Is. 8d. 

A 36" foot-rule is a convenient size to have. 

Metal shears are required for cutting sheet brass 
and copper, price 2s. 

A small hammer for riveting is useful, price Is. 3d. 

A metal square called an " engineer's " square is 
necessary, price Is. 6d. 

A set of turning chisels and gouges are required 
for wood-work and metal-work. Sets of these can 
be purchased in blocks, at prices from 10s. to 
17s. 6d. 

A lacquering plate is a plate of iron to be heated 
over the fire. Work to be warmed for lacquering is 
laid upon it. 

Lacquering. Bright brass when finished must be 
lacquered to prevent its getting tarnished. Brass 
lacquer can be purchased, and is applied with a 
small brush ; the metal having been previously 



TOOLS USED IN MODEL ENGINE-MAKING, 23 

heated in the spirit-lamp just hot enough for the 
hand to bear. 

Brazing is rather too difficult for an amateur, 
and we will not describe the method here. For the 
engines given in this work no brazing is required, 
except for the internal fire-box and fire-tube ; but 
it is best to have the fire-box made by a copper- 
smith, as will be shown further on. 



r? c c3 



CO 




Fig. 10. 

Soldering-bolts (see Fig. 10). Soldering is re- 
quired for model-making. This can be easily done 
and joints made perfectly steam-tight, after a little 
practice. We recommend two light copper bolts : 
a straight one, and one bent at right angles to the 
handle; and for a flux do not use resin but spirits 
of salt, made by saturating hydrochloric acid with 
strips of metallic zinc, till no more hydrogen is 
evolved ; this forms zinc chloride. Keep the solution 






24 MODEL ENGINE CONSTRUCTION. 






in a well-corked bottle. By means of a wire touch 
the parts over with the solution before soldering, 
after having scraped them clean. 

Method of soldering. Take the soldering-iron, 
warm it in the fire, with a file clean it thoroughly 
near the point on both sides, and if at the proper 
heat, after rubbing a little spirits of salt upon it, 
and touching it with a stick of soft solder, the 
solder will stick to the iron, and make it appear 
bright. This operation can be done at the proper 
heat (which is found out after a little practice), 
and is called " tinning the bolt," and must be 
done before soldering. After being used much, the 
" tinning will come off, and must be again renewed 
by the same process. After "tinning," warm the 
soldering-bolt in the fire; never let it arrive at a 
bright red heat, as this is too hot for use. Before 
beginning to solder, lay a stick of solder at one side, 
and a bottle with spirits of salt at the other. If 
you are going to solder two pieces of brass together, 
first clean both pieces by filing all round, where they 
are to join ; sprinkle a little spirits of salt on as a 
flux, to remove the tarnish ; then, with the soldering- 



TOOLS USED IN MODEL ENGINE-MAKING. 25 

bolt touch the stick of solder lightly, when a piece 
will adhere to it. Put the bolt with the solder upon 
the brass over the joint, and hold it on for a second 
or two, when the solder, if all tarnish be removed, 
will adhere to each piece, and they will become 
tinned over like the bolt. After tinning, bring the 
two pieces together, put on more spirits of salt, 
touch the solder-stick again with the bolt, and hold 
it over the pieces of brass for a little time to 
"sweat" in the solder; when cool, the two pieces 
will be found to adhere firmly together. At first, 
one is apt to make a clumsy job, and put on too 
much solder, but a little practice will enable the 
amateur to make a neat job and ( a first-rate 
joint. Brass, as well as iron and copper, must be 
tinned before attempting to solder two pieces to- 
gether. Tin plate does not require tinning. Iron 
is more difficult to solder than brass, and for copper, 
the soldering-bolt must be made a little hotter than 
for brass. 

Metals. Brass wire is generally hard, and can be 
softened by being made red-hot. Castings are the 
softest, and can be rendered hard by hammering, 



26 MODEL ENGINE CONSTRUCTION. 

and soft by being made red-hot. It is best always 
to use new files for this metal. 

Gun-metal is much harder than brass to work. 

Copper is softer than brass. 

Iron is much harder than brass. Water as a lubri- 
cator assists in turning and sawing; in drillings it 
requires oil. It takes the cut off files rapidly, and 
old files will cut it just as well as new ones. 

Note. — Never use the same files for brass and 
iron, but keep separate tools for each kind of 
metal. 

Bright brass may be finished with emery powder 
and oil, the burnisher, or by dipping. This last 
consists in making the work free from grease, and 
then "dipping" it clean and warm into nitric acid 
(aquafortis), and when it has "taken," rinsing 
rapidly in clean cold water and drying quickly; 
this makes the work beautifully bright. 

To temper drills. The small-sized drills had best 
be purchased, or made out of steel knitting-needles ; 
the larger sizes can be made out of a steel bar by a 
blacksmith; these must be each ground to a point 
and then tempered, when they are ready for use. 



TOOLS USED IN MODEL ENGINE-MAKING. 27 

Heat the drills (use a Bunsen burner for the small 
sizes) in the fire until red-hot, about the colour of 
red lead ; if small plunge them into oil or cold fat ; if 
large, into water; clean them bright with emery 
cloth, again heat them until the edge polished is a 
golden or straw colour, then quench in water, and 
when ground they are ready for use. If the steel be 
brittle, let them run lower to a blue colour. A 
blow-pipe is good to get the proper temperature 
with when acting on a gas-jet. 

Fine brass tubing is sold in foot lengths, each 
length costing 6d. The finest is T V bore, the 
next ^V' bore, and the next again J". For larger 
sizes ordinary gas-tubing does well enough. 

A hand-drill is necessary, one that takes drills 
from \" to T y ' is a useful size ; the chuck is adjust- 
able for the different sizes of drill-points, and these 
are supplied along with the tool. When using it, 
the drill is kept pressed against the work with the 
left hand, and the wheel that causes the drill to 
revolve driven by the right hand. Prices, 5s. 6d. up 
to 12s. 

An upright vertical drill for fastening to a bench 



28 MODEL ENGINE CONSTRUCTION. 

is useful for all sizes of drills up to |". Prices range 
from £2 up to £2 10s. 

Drill-points can be obtained from Mr. Lee, 203, 
Shaftesbury Avenue, London, who supplies one 
dozen, varying in size from T V up to yV, f° r 
the sum of Is. These drill-points are very good 
ones. 

A good illustrated catalogue of "American" tools, 
with prices, can be also got from Mr. Lee, and 
should be in the hands of every amateur. 

In case the amateur should prefer to make his 
own drills, we will conclude this description of the 
tools by saying that very good small-sized drills can 
be made from steel knitting, and sewing-machine 
needles. The former can be cut into lengths of 1\'\ 
and a drill made out of each length ; one drill can be 
made from the latter (broken needles do for this 
purpose). File the steel wire slightly tapering at one 
end, and then spread the point with a good strong 
blow from a fairly heavy hammer (a series of light 
blows will not do at all), grind the point to a 
sharp cutting edge on the grindstone, and the drill 
is ready for use — or if it requires to be tempered, 



TOOLS USED IN MODEL ENGINE-MAKING. 29 

instructions have already been given how to do this 
operation. 

A word or two about a workshop may not be out 
of place. A spare room in the house may be utilized 
as such, or a wooden structure may be erected 
outside. Whichever is adopted, the workshop should 
be well ventilated, free from damp, have plenty of 
light admitted, and be tolerably warm. A fire-place 
or small stove is useful for heating soldering-bolts 
in, and warming the place during winter. The shop 
must be well stocked with engineering tools, and 
these should be arranged in some kind of order, so as 
to have "a place for everything." The lathe ought 
to be fixed near the window, so that a good light 
is thrown upon the work when turning ; all the 
turning tools may be conveniently kept in a box 
fixed to the lathe-stand. A joiner's bench is neces- 
sary, as well as a few tools for wood-working and 
pattern-making. A forge can be dispensed with, 
but if there be a supply of gas, a Bunsen burner is 
useful, for tempering fine-sized drills, etc. A vice, 
with 4" or 5" jaws, should be fixed at a convenient 
height from the floor, to suit the operator, as well as 



30 MODEL ENGINE CONSTRUCTION. 

a smaller size for holding fine work when filing. A 
grindstone ought to be fitted up, so that it may be 
driven by hand, or preferably by foot, and is useful 
for grinding tools, as wood-cutting and turning tools 
must always be kept very sharp; and there should 
be some arrangement to keep the stone moistened 
with water when in use. Perhaps the best way is to 
keep it half immersed in a water-trough, and the 
water can be run out of the trough by a cock when 
not in use. If the amateur goes in for locomotive 
building, it is a good plan to fit up a permanent 
length of railway, fixing it on a board near the wall, 
on one side of the shop. This can be raised to any 
convenient height, and is always ready for running 
the locomotives upon, when it is desired to do so. 

For pattern-making tools see page 308. 

A few of the electros for reproducing some of the 
drawings of the tools have been kindly lent by the 
Britannia Co., Colchester. 



CHAPTER II. 

THE BOILERS AND THEIR FITTINGS. 

We first describe a horizontal boijer without a 
flue-tube, suitable for hanging over a kitchen fire, 
and useful for testing small engines when making 
them. Next, a locomotive boiler with an internal 
fire-box, fire-tube, and a water space all round the 
fire. This boiler raises plenty of steam, as from its 
construction a strong draught of air is kept rushing 
through the fire-box, fire-tube, and funnel when at 
work. Lastly, a vertical boiler, constructed in a 
similar way to the locomotive boiler. 

The horizontal boiler (see Fig. 11a) is made 
entirely of No. 20 sheet brass, riveted and soldered 
together, and when complete is 10" long and 6" in 
diameter. Cut a sheet 19"xl0", and bend it into 



32 



MODEL ENGINE CONSTRUCTION. 



a circular shape, with a diameter of 6" ; a sheet this 
size allows of an over-lap of fully J''. Clean the 
ends that overlap with emery paper or dilute nitric 
acid ; this makes them take on solder when chloride 




h /o 



Fig. 11a. — Boiler for Kitchen Fire (| full size). 

of zinc is applied. Fasten these ends together along 
the longitudinal seam here and there with solder, 
then drill three holes for rivets which pass through 
the over-lap, one near each end, and one near the 



THE BOILERS AND THEIR FITTINGS. 33 

centre ; put through three small copper rivets from 
the inside, and rivet them firmly on the outside. 
The end rivets may be fixed against a leg of the 
vice when riveting; but for the centre one it may 
be necessary to pass the boiler over an iron block 
held horizontally in the vice, and then rivet while 
the head of the rivet rests on this block. Solder 
the shell firmly together along the seam and over 
the rivet heads. For the ends cut out two circular 
pieces of sheet brass, each 6f" diameter; this size 
allows of a ■£$■" collar all round, which is to be 
turned down over the barrel. The collar is made by 
hammering the end over a circular block of hard 
wood, turned to the same diameter as the barrel, 
and long enough to be gripped in the vice ; tin the 
inside of the collar with solder, and also a circular 
strip around the edge of the barrel at both ends, 
place the end in position, and solder it firmly to 
the barrel ; do the same with the other end. Pass a 
stay through the boiler, and for this purpose drill a 
small hole through the centre of each of the boiler 
ends; take a piece of brass wire I" thick — brass 
is used, as this does not rust — and about 11" long, 

D 



34 MODEL ENGINE CONSTRUCTION. 

tap a thread at each end, fully J" in length, screw 
a nut on one end, cut the wire short, and hammer 
the edges all round down on the nut to keep it 
firm; solder it on, and pass this wire through the 
boiler from one end, and screw the other nut on 
to the opposite end ; bring it up to rest against the 
end of the boiler, and solder both the nuts over. 
This stay makes the boiler strong enough to resist 
pressure. Arrange the boiler so that the longi- 
tudinal seam is placed near the top or upper part 
when the fittings are on. These consist of a -|" 
gas stop-cock, and a foot or so of tubing, a screw 
plug or water-filler that screws into a ring soldered 
on the boiler, and a lever safety-valve (with a 
weight), y 3 g-" diameter at narrowest part of seat ; 
holes must be drilled in a straight line along the 
top of the boiler, and each enlarged with a rimer 
to the size suitable for the corresponding fitting; 
then solder on these fittings. A weight of about 
a quarter of a pound, hung at a distance of 3" 
from the fulcrum, will be suitable for this size of 
valve. Cut two strips of sheet brass or copper, 
each 19" x 1", rivet them together to form two rings, 



THE BOILERS AND THEIR FITTINGS. 35 

of a size that will just slip over the boiler, one from 
either end, before the ends are put on, and be a tight 
fit ; these can be fixed with solder in certain parts, 
and are used to give extra strength. Any black- 
smith will make and rivet together a small iron 
frame, which will sit on the hob over the kitchen 
fire, or on the grate, and support the boiler when 
in use, but it must be so made that the bottom 
part of the boiler is exposed direct to the flames. 
Or if there be an arrangement in the fire-place 
of a swing with hooks, and it is desired to hang 
the boiler like a kettle, this is easily done by 
purchasing two strong rings such as pictures are 
hung by, file off the screw-thread from the stems, 
as it is too rough for our purpose, tap a new thread, 
and make nuts to suit, and all you have got to do is 
to drill two holes in the upper part of the boiler, 
one near each end, in line with the fittings, insert 
the stems of the rings, and screw the nuts on inside. 
Of course all this must be done before the boiler 
ends are fixed on, and any of the fittings attached. 
Take a strong piece of copper wire, bend it into a 
U -shape, insert the free ends through the rings, 



36 MODEL ENGINE CONSTRUCTION. 

and twist them with pliers, so that they will not 
come out. By means of a hook passing through 
the wire loop, the boiler can be hung any distance 
above the fire. Solder a small cock into one end, 
to show when the boiler is about three-quarters full 
of water. When in use, temporary attachment is 
made between the boiler and any engine by india- 
rubber tubing (different sizes can be purchased), 
one end being pushed over the steam-pipe — which 
should project outwards for a considerable distance 
from the boiler, as it gets very hot for the operator 
if too near the fire — and the other end attached to 
the steam-pipe of the engine, which rests on a chair 
or table. To prevent the rubber tubing being blown 
from off the ends of the steam-pipes, it should be 
tied on at both ends. The disadvantage of this 
india-rubber method of attachment is, that if the 
pressure rises too high in the boiler, the rubber 
tubing will burst with a loud report and be rendered 
useless ; so that it is perhaps preferable to make the 
attachments by means of coupling screws and brass 
tubing temporarily soldered together ; different sizes 
of tubing can be joined together, so that though the 



THE BOILERS AND THEIR FITTINGS. 37 

boiler steam-pipe is T y bore, that supplying the 
engine can be reduced, if necessary, to <£%" bore when 
testing a small-sized engine. 

Locomotive boiler (see Sheet No. 1). All the 
locomotive boilers we take up here are made on the 
same principle, though they vary slightly in size. 
The boiler barrel and outer fire-box is made of No. 
24 sheet copper, the piece forming the barrel and 
outer fire-box is 10|" X 8f". There is an internal 
fire-box and fire-tube made of No. 21 sheet copper 
(the thinnest size that can be brazed). This article 
must be brazed together in all the joints, and is 
best made by a coppersmith, as brazing is difficult 
for the amateur. The fire-box is composed of three 
separate pieces, one bit forming the two sides and 
top; these must be flanged outwards at the foot. 
The back or fire-door plate has an oval hole cut in 
it, and is flanged at the foot. The front plate is also 
flanged, and has a circular hole cut in it for the fire- 
tube to pass through, there being one fire-tube only 
that goes to the smoke-box. The front and back 
plates must be cut rather larger than the dimensions 
given, to allow of a small collar being turned down 



38 MODEL ENGINE CONSTRUCTION. 



over and brazed to the sides when putting together. 
A small oval sheet-copper tube is brazed together, 
and also brazed into the fire-door hole; this forms 
the coal-shoot or fire-hole ring, and must project 
outwards, so as to pass through the outer fire-hole 
when the boiler is put together. The fire-tube is 
made of copper brazed into the fire-box, and also 
into the boiler tube-plate, and the ends can be 
flanged down on the plates as well ; the longitudinal 
seam is also brazed. When this fire-box is finished 
the barrel and outer fire-box must be bent into 
shape by hand, and fitted over the inner fire-box, 
the barrel being made of the correct diameter and 
soldered along the longitudinal seam, which is un- 
derneath, no rivets being required along this seam ; 
flange the tube-plate over the front of the barrel all 
round, and solder them together, having previously 
tinned the parts. Cut out the outer fire-box back 
plate, cut a fire-hole in it, and pass the projecting 
tube from the inner fire-box through it ; beat down 
the ends to form a collar — this must be done inside 
as well. The collar fixes the plate; solder it all 
round, do the same to the barrel after flanging. It 



TEE BOILERS AND THEIR FITTINGS. 39 

will be noticed that the inner fire-box has a pro- 
jecting collar and flange all round underneath, which 
ought to be very carefully brazed at the corners ; for 
unless this is done, it is apt to leak at these parts. 
The use of this projecting part is, that when the 
boiler is put together, this collar projects outwards 
all round against the sides, the front, and the back 
of the outer fire-box, and forms the foundation-ring. 
The space between the fire-boxes is called the 
" water space." Solder the parts where they come 
together all round carefully, after tinning them to 
take on solder ; sweat the solder well in between the 
joints to render the boiler thoroughly water-tight, 
and to do this the boiler must be turned upside 
down and fixed against a support of some kind — 
two blocks of wood do very well. Fit on the front 
plate of the fire-box by cutting out of it a piece of 
a circular shape, to form a concavity to fit the circle 
of the barrel, flange the sides, and solder together. 
The boiler is now ready for staying. We proceed in 
the same way as before. Three small copper rivets 
may be quite sufficient ; two might do, one on either 
side, but it is best to put one in front between the 



40 MO DEL ENGINE CONSTRUCTION. 

fire-boxes as well. The back plate does not abso- 
lutely require a stay, as the fire-hole ring acts as 
one ; still, it is best to put one through under the 
fire-hole (see Sheet No. 1). The fire-boxes must 
be firmly stayed together to stand pressure, as this 
is the weakest part in the whole boiler. 

Be careful to insert the rivets below the level of 
the fire-door, as it is as well to have no openings 
above that level, for fear of the water getting short 
and the solder melting. The outer fire-box projects 
further downwards in front and at the sides than 
at the back, where it is cut off short ; this is done 
to leave a space for the lamp to pass to the fire-box. 

The spirit-lamp is made of tin, and the neck is 
left of such a width and length, that when it is 
in position in the fire-box a clear space of about 
half-an-inch is left between it and the fire-box, 
both in front and at the sides, for air to pass to 
the wicks and support combustion. 

The smoke-box is made of tin of a circular shape, 
surrounding the barrel; a rivet is put through 
underneath where the ends overlap, to keep it 
circular. A front plate of tin, having a 1" hole cut 



TEE BOILERS AND TEEIB FITTINGS. 41 

through it, can be flanged and riveted by very fine 
rivets made of copper wire to the smoke-box, as 
solder will melt by the heat. A small circular door, 
flat or dished, — the latter is rather difficult to do, — 
is hinged in front by a hinge made of sheet brass 
and a wire, which must be riveted to the smoke-box 
and to the door. This door opens and shuts, and 
when shut it fastens by means of a small brass 
handle. A thin strip of brass is riveted across the 
opening of the smoke-box inside, and a T-headed 
bolt passes through a slot in the brass; the flat of 
the head corresponds with the breadth of the slot. 
It is turned a quarter round by means of a handle, 
and then the outer handle is tightened upon 
the inner one in lock-nut fashion. The funnel is 
about f" wide at the root, made of tin, soldered 
and riveted together. It is fixed on the smoke-box 
by a collar, which is fastened by two rivets, a hole 
being first cut in the smoke-box of the same size 
as the funnel over which it is placed ; a bit of 
half-round wire soldered round the top will form 
the beading, but this is unnecessary. When placed 
on the barrel, the smoke-box overlaps the front of 



42 MODEL ENGINE CONSTRUCTION. 

the boiler by about §-", and to prevent it from 
passing farther backwards, a copper wire is neatly 
soldered all round the barrel for the edge of the 
smoke-box to rest against, when it is pushed on 
to the front of the boiler over the tube-plate. 
The smoke-box should never be attached by solder 
to the boiler, because it is necessary sometimes to 
take them apart; but white lead can be put round 
the joint to keep it air-tight. 

The fire-door is made of copper, oval in shape, 
and is hinged, the hinge being riveted to the 
fire-door, and soldered to the boiler. A small latch 
handle is pivoted to a rivet, and passes into a 
keeper when the door is shut; the keeper, of 
sheet brass, is soldered to the fire-box. This boiler, 
if properly made, will raise steam of 20 to 30 lbs. 
pressure per square inch, and stand it quite safely. 

The fittings are a dome, with or without a lever 
safety-valve, a screw-plug for filling the boiler with 
water, a ■§•" spring safety-valve which will relieve 
the boiler of excessive pressure, and a small gauge- 
cock to test the height of the water in the boiler 
when filling it. The steam-pipe, -|-" bore, passes 



THE BOILERS AND THEIR FITTINGS. 43 

down through the smoke-box to the cylinders, start- 
ing inside the upper part of the dome; the pipe 
is soldered where it passes out through the front 
tube-plate. Steam is controlled by a -J" stop-cock 
placed in the smoke-box, and into which the steam- 
pipe is screwed, and below the cock there is a 
coupling screw or union for further attachment by 
tubing to the cylinders. This cock is opened and 
shut, by simply drawing out and pushing in a 
hinged wire lever, or regulator (pivoted to the back 
of the fire-box), and this is done by means of a wire 
passing through a T V' brass tube, which extends 
through and is soldered to the boiler at the tube- 
plate and back of fire-box. This arrangement of the 
wire passing through a tube, when inside the boiler 
saves making two stuffing-boxes for the regulator- 
rod to pass through, as these are difficult to make 
and keep steam-tight when very small, and the tube 
serves the same purpose. A full-sized drawing of 
this arrangement is given on Sheet No. 11, B. 

The spirit-lamp is the same as that on Sheet No. 
12, on which will be found a plan and elevation. 
It is made of tin plate soldered together, the rect- 



44 MODEL ENGINE CONSTRUCTION. 

angular tank sits behind the fire-box ; a long circular 
funnel of tubing or tin, with an elbow-joint below, 
is soldered at the back of the tank on one side, for 
the purpose of pouring in spirits of wine to the 
wicks when steam is up. The neck of the lamp is 
of tin, similar to the tank, but narrower, so as to 
allow a clear space of half-an-inch all round and 
in front, between it and the sides of the inner 
fire-box, for admission of air. The lamp can be 
pushed in and drawn out of the fire-box as re- 
quired. It carries on the neck a number of wick- 
carriers, set in two rows ; these are simply ■£ w " 
holes drilled in the top plate and stuffed with 
cotton wicks, or asbestos twine. As a rule, we 
allow twelve or fourteen of these small wicks to 
burn in a boiler having a fire-box (measured below 
the bottom of internal fire-box) about 3 T y x 2f " 
as fewer than these will not keep up sufficient 
steam. 

Remarks. — The boiler will raise steam up to 30 lbs. 
pressure per square inch. Its method of construction 
was only arrived at after one or two experiments 
carried out on small boilers by ourselves, and we 



THE BOILERS AND THEIR FITTINGS. 45 

believe that its steaming qualities depend entirely 
on the following modifications. 

1. Increasing the depth of the inner fire-box, by 
carrying the crown upwards to near the top of the 
outer fire-box, and having a circular crown, as this 
increases the heating surface. 

2. Instead of making the boiler multitubular, 
adopting one fire-tube only, for in small boilers, 
if there be two or three tubes, the draught gets 
choked, and steam rapidly falls. 

3. Discarding an ash-pan, and leaving the fire- 
box open underneath, with a space of nearly -J-" 
between the sides, and those of the lamp, for 
admission of air. 

4. Cutting the blast-pipes (there are two) short, 
so that their orifices open and discharge steam 
about the centre of the front of the fire-tube ; 
their orifices are slightly flattened to increase the 
pressure. More steam is generated than when pipes 
are led up to the root of the funnel. 

5. Adopting a wide funnel (one less than about 
-§" diameter is rather narrow, to make the boiler 
draw well). 



46 MODEL ENGINE CONSTRUCTION, 

6. Not firing the boiler with one or two wicks, 
as is done in some model boilers, but using a great 
number, so as to generate more steam than the 
cylinders can use. 

The above boiler will drive a pair of cylinders 
each \" bore and 1" stroke, or one cylinder £" 
bore and 1^" stroke. 

1 Note. — With such a number of wicks burning 
inside the fire-box, after a time the spirit-tank is 
apt to get a little hot and cause evaporation of the 
spirits (seen by fumes coming out of the funnel 
leading to the lamp), in which case fresh methylated 
spirits must be poured in to keep the wicks burn- 
ing ; but there is not the slightest danger of an 
explosion of the spirit taking place. 

A much larger and stronger boiler can be made 
by doubling the dimensions over all of those given 
on Sheet No. 1, and using stronger material, while 
still adhering to the same method of construction. 
It is a mistake to make a boiler multitubular of 
a size less than a half-horse power, consequently 
we adopt one fire-tube as before. Make the barrel 
and outer fire-box from a single sheet of No. 16 



THE BOILERS AND THEIR FITTINGS. 47 

sheet brass ; the internal fire-box, fire-tube, and 
tube-plate from the corresponding copper sheet No. 
18. When put together the boiler must be brazed 
at every joint, both at the outside joints and at 
those connected with the inner fire-box, so that it 
is best made by a coppersmith, to insure its being 
strong and able to stand 60 lbs. pressure per square 
inch. Pass eight T V' copper rivets through between 
the fire-boxes on each side, and in front and behind ; 
after riveting together, their heads should be brazed 
over, both on the outside and inside of the fire-box. 
A longitudinal stay is not required. The fittings 
should be brazed to the shell, and these should 
include, besides a half-inch safety-valve, two gauge- 
cocks, a glass water-gauge, and a clack-valve for a 
pump. The smoke-box and funnel are made of 
sheet brass. A lamp can be made of thick tin plate, 
with wicks to burn methylated spirits of wine or 
oil; but a better plan is, to fit a brass grate low 
down inside the fire-box (leaving it all open under- 
neath), which will burn small blocks of wood steeped 
in methylated spirits of wine, paraffin, or ordinary 
oil, and this will raise abundance of steam. 






48 MODEL ENGINE CONSTRUCTION. 

Vertical boiler (see Sheet No. 2). This form is 
easier to construct than the last. It is made of 
No. 24 sheet copper cut to a size of 6-J-"x10-jV' J 
this is bent into a circular shape, and forms the 
outer shell. The internal fire-box is made of No. 21 
sheet copper, and should be done by a coppersmith, 
having all the joints brazed together. It is made 
in the same way as the previous one described, but 
is circular; there is a flat top or crown, through 
the centre of which the funnel passes. The fire-hole 
is cut to dimensions of an oval shape, and a piece of 
copper brazed in to form the fire-hole ring is left 
long enough to pass through the outer fire-hole 
when put together. When the fire-box is completed, 
take the sheet which forms the outer shell and 
measure off the distance for the fire-hole ; make the 
outline oval in shape, drill out the piece, and file to 
outline. Now bend the metal into a circular shape 
to the correct size, then widen it a bit, and insert 
the fire-box from the lower end, the funnel passing 
upwards through the boiler. Flange the fire-door 
ring and solder it on the inside of the outer fire-box, 
bend the shell again to the correct shape, solder all 



THE BOILERS AND THEIR FITTINGS. 49 

along the longitudinal seam — a small rivet may be 
put through the overlapping edges near the top, 
and riveted against a small block of iron fixed 
in the vice, and which passes inside the boiler. 
Another small rivet may be inserted in line with 
this one, and must pass through the lower part of 
the inner fire-box below the water-line, where the 
metal is curved outwards to meet the outer fire- 
box, forming the foundation-ring, and connects 
together the two fire-boxes; the heads of the 
rivets must be soldered over, and solder be put 
in all round the joints of the outer and inner fire- 
boxes, and for this purpose the boiler should be 
turned upside down. An opening must be made 
at the foot under the fire-door 2|" x -fw", to admit 
air to lamp, and clean out the ashes. At one corner 
this opening may be enlarged to -f" (not shown 
in drawings), to allow the funnel of the lamp to 
pass through when in situ. This opening can be 
cut after putting the boiler together, by slitting 
it at the ends to the required depth with metal 
shears, breaking out the piece with pliers, and 
then filing to outline. The crown is made of 

E 



50 MODEL ENGINE CONSTRUCTION. 

sheet copper, 3 J" diameter, to allow of a flange, 
which in this case is put outside the shell (instead 
of inside, as in large boilers), for the purpose of 
strengthening the boiler more when soldered. The 
funnel passes through the centre, and is soldered to 
the crown, or if preferred, the boiler crown could be 
brazed to the funnel by the coppersmith, and so 
increase the strength still more. A sheet-brass door 
— one plate only — is cut rather larger, but of the 
same shape as the fire-hole, attached by rivets to a 
hinge, which in this case must be soldered to the 
boiler ; there is also a keeper and latch to fasten 
the door to. 

We insert the following fittings : a T V' cock, so 
placed as to indicate when the boiler is three- 
quarters full of water ; a second cock is put in at a 
height just under the fire-box crown ; when work- 
ing, while water continues to be blown out of the 
lower cock, the boiler may be safely run without 
fear of the water getting too short. The boiler will 
steam about twenty minutes with one charge of 
water. A small water-gauge can be made or pur- 
chased, and inserted, so that the water stands well 



THE BOILERS AND THEIR FITTINGS. 51 

up in it, when the boiler is three-quarters full. A 
§" water-plug or filler is soldered into the crown, 
as well as a spring or lever safety-valve, fully ■§■" 
diameter at its seat. A cock controls the supply of 
steam to the cylinder of the engine, which can be 
attached by tubing and coupling-screws. This boiler 
will drive a T V' bore cylinder and 1" stroke very 
well. The boiler could be fitted with the force- 
pump (see p. 72), but this would require to be 
driven by hand. 

The spirit-lamp is made of tin (see drawings). 
It consists of a circular tank soldered together, 
about J" deep, and of a size that will fit easily 
inside the fire-box. On the top a number of small 
holes are drilled, which act as wick-carriers; about 
a dozen will be required to keep up steam in a 
boiler of this size, if each hole is ^-" in diameter. 
Plenty of wicks must burn in these tubular boilers ; 
to try to keep up an active supply of steam with 
one or two wicks only burning, as is done in 
most models, will render these boilers pretty nearly 
failures, for no strength of steam can be kept up, 
with an engine running at the same time. Spirits 



52 



MODEL ENGINE CONSTRUCTION. 



of wine is poured into the lamp through the vertical 
lamp-funnel when required, to keep the flames brisk 
when steam is up, for with such a big fire burning it 
requires constant stoking. The boiler is not fixed to 
a wooden stand, but is simply lifted off and set down 
upon the lamp resting on the table. When the fire 




Fig. 11b. 

is to be " drawn," it is best with a cloth to lift the 
boiler off the lamp, and then smother the flames 
with the same cloth rapidly brought down, so as to 
extinguish them. The flames do not blow out very 
easily, and not at all when in the fire-box, while 
to allow the methylated spirits to burn out is apt 
to char the wicks, and they do not stand long. A 









THE BOILERS AND THEIR FITTINGS. 53 

flange can be soldered or riveted all round the boiler 
at the foot to steady it when at work. The inner 
fire-box, being of a circular shape and brazed 
together, does not require to be attached by stays to 
the outer' shell, as the circular shape tends to resist 
the pressure more than the flat-sided fire-box in the 
locomotive boiler does. 

Boiler Fittings. 

The safety-valve (see Fig. 11b) is a circular, 
steam-tight valve set on the boiler. Its object is to 
prevent the steam pressure in the boiler exceeding 
the working pressure. The pressure on the outside 
of the valve is produced by a lever and weight, or by 
a spring, as in the case of locomotive safety-valves. 
The valve casting is a brass casting turned on the 
lathe, and a central hole is drilled through it. At 
the top this hole is widened, and made of a conical 
shape, for a short distance downwards, and this 
forms the valve-seat proper. The valve itself is a 
piece of circular brass rod turned on the lathe, and 
made conical round the edge, so as to fit the seat in 
the casing ; a small spindle, or stalk, is turned on 



54 MODEL ENGINE CONSTRUCTION 

the valve below the conical edge, which guides the 
valve in rising and falling into its seat. The valve 
must be ground with emery powder and oil into its 
seat, so as to be rendered steam-tight. A brass 
fulcrum must be slotted at one end, and screwed by 
its other end into the rim, or flange of the valve- 
casing, and a piece of steel or iron wire, filed or 
hammered flat to form a lever. This is drilled at 
one end to take a pin, and by it is pivoted in the 
slot of the fulcrum. In some cases, this lever simply 
rests on the top of the valve ; in other cases, the top 
of the valve is prolonged upwards above the casing, 
and the lever is pivoted to it, as it passes through 
a slot which has been made in the top part of the 
valve. The weight, which is hung over the free end 
of the lever, is a piece of brass, iron, or lead ; the 
projecting part by which it hangs must have a slot 
cut in it, so as to be able to slide the weight along 
the lever. A hole can be drilled through the slot, 
and a set-screw attached, which, when tightened up, 
will keep the weight fixed at any part of the lever, 
as desired. The valve-casing should be soldered or 
screwed into the boiler. 



THE BOILERS AND THEIR FITTINGS. 55 

A spring safety-valve (see Fig. 12) is similar to 
the above, but, if of the lever type, the end of the 




Fig. 12. 



lever is pulled down by a Salter's spring-balance, 
which is generally graduated. The balance can be 



56 



MODEL ENGINE CONSTRUCTION. 



made with a small spring acting against a piston, 
moving up and down in a small tube, closed at both 
ends. The piston-rod passes vertically through a 
hole drilled in the end of the safety-valve lever, and 
at its upper end is screwed, and provided with a 
nut. The valve is held down against the steam 
pressure by means of the spring in the tube, pulling 
the lever downwards. The nut can be slackened, or 




Fig. 13. 

tightened up, as required to suit the steam pressure. 
The spring-balance at its lower end is pivoted to 
a bracket, which is soldered or screwed into the 
boiler. 

A direct-acting spring- valve (see Fig. 13) is a good 
one for small models. This can be easily made from 
the instructions given, or it may be purchased, of 
any suitable size, from the model-maker's. 



THE BOILERS AND THEIR FITTINGS. 59 

The rule, to find what pressure of steam a valve 
will hold, is to " divide the length of the lever by 
the distance from the centre of the valve to the 
centre of the fulcrum; multiply by the amount of 
the weight in pounds, and divide by the area of the 
valve in inches." To be very exact, an allowance 
must also be made for the weight of the lever and 
of the valve itself. 

To find the area, in square inches, of a circle of 
a given diameter. Square the diameter, and mul- 
tiply by '7854, or multiply 3*1416 by the square of 
the radius. 

A pressure-gauge (see Figs. 14 and 15) is an 
instrument for indicating how much the pressure of 
steam is above that of the atmosphere. For very 
small models these are not required, and for small- 
power boilers it is best to purchase a Bourdon or a 
Schaffer gauge, as these instruments are accurate, 
and can be relied upon. However, for those who 
care to make one, we describe a gauge as made by 
ourselves, which does well for models. It consists 
of two short pieces of brass tubing, -§-" diameter, 
both having a circular collar soldered on to them, 



60 MODEL ENGINE CONSTRUCTION. 

where they come together; or this might be a 
casting, with three small bolts passing through the 
collars to tighten them up ; a thin rubber diaphragm 
(B) passes between them. The upper piece carries 
a brass ring into which a dial is fixed, the front' 
being covered over with glass : this forms the gauge 
proper; the back is a circular plate which fits on 
to it. The lower tube is screwed on to a bent 
syphon tube from the boiler. A small flat disc, or 
piston (A), rests on the rubber diaphragm, the stem 
of which is flattened and passes up to the top of 
the gauge (being slotted longitudinally to allow the 
pointer-stem G to pass through it), and connects 
with a bell-crank D, which, by means of a lever, 
pivots on to the end of a drag-link E, attached to a 
tooth- quadrant F. This quadrant gears inside with 
a small pinion fixed to the pointer-spindle ; a strong 
watch-spring has its inner end attached to this 
spindle by a pin, and its outer end to the case of 
the gauge H ; this ensures the pointer returning 
to zero when the pressure is removed. When the 
pressure is greater than that of the atmosphere, the 
rubber bulges upwards, and when it is less it bulges 



THE BOILERS AND THEIR FITTINGS. 61 

downwards ; these motions, being proportionate to 
the pressure per square inch, are correspondingly 
indicated on the graduated dial by the pointer. 
When graduating the gauge, it must be tested by 
attaching to a large boiler, and marking the dial 
to agree with that of the boiler as steam is raised. 
Our gauge is If" in diameter, and indicates up to 
10 lbs. per square inch; but by using a stronger 
spring it might be made to indicate a higher 
pressure than this. Instead of the rubber, a 
diaphragm of thin hard sheet brass might be 
used, to the centre of which a needle-point is 
fastened. 

A glass water-gauge (see Fig. 16) is a device for 
ascertaining the height of the water in the boiler. 
There are three cocks in the most perfect models : 
the upper one is fitted into the boiler opposite to 
the steam space, the middle one opposite to the 
highest part exposed to the flames, the lower one 
below the gauge. The upper and middle cocks 
allow steam and water to pass; these meet in the 
glass tube, and stand at the same level as in the 
boiler; the lower cock is to blow out and keep the 



02 



MODEL ENGINE CONSTRUCTION. 



gauge clean. To make it, take two brass blocks, drill 
i ole through one of them for about half its length, 
make this hole much wider than the glass tube, fit 





Fig. 16. 



a stuffing-box gland on to one end, and screw a cock 
into the other. Next drill a hole at right angles to 
the first one, and screw a cock into it ; this block 



THE BOILERS AND THEIR FITTINGS. 63 

forms the bottom of the gauge. Take the other 
block, fit it just in the same way as this one, 
except that the hole which is drilled through it lor 
the glass tube to pass should have a plug screwed 
in at the upper end instead of a cock ; drill a hole at 
right angles as before and screw in a cock. It will 
now be seen that there are two cocks, one in each 
block, opening at right angles to the glass tube. 
Screw both of these cocks into a brass plate, or 
direct into the boiler. To insert the glass tube, cut 
it of the proper length, so that when resting in 
the upper and lower blocks it will not obstruct 
the passages through the cocks (which are at right 
angles to it), and lead from the boiler ; unscrew the 
plug from the upper block, insert the glass tube, 
and push it down till it has entered the lower 
stuffing-box; screw the plug down on the tube, 
unscrew the stuffing-box glands above and below, 
and wind tow round the tube at both ends, where 
it enters the stuffing-boxes ; then screw the glands 
both up on the packing, and the gauge will be 
found to be perfectly steam-tight. 

A simpler gauge (see Fig. 17), without cocks, is 



64 



MODEL ENGINE CONSTRUCTION. 



made as follows. Take two small brass blocks, drill 
each of them only half-way, or nearly so, to their 
centre, leaving the hole large enough to admit the 
glass tube. Now drill two smaller holes in the 
blocks at right angles to the previous ones, and 
instead of inserting a cock in each, put in, by 



nA 



<EZ3> 



Fig. 17. 

screwing or soldering, a bit of brass tubing about -J" 
long, the bore of which communicates with the 
boiler and the glass tube, through the hole in the 
block previously drilled at right angles to it. Each 
block is firmly soldered to a small brass plate A, 
each tube passing through a hole in the plate. The 



THE BOILERS AND THEIR FITTINGS. 65 

glass tube is inserted by one end into one block, and 
by the other end into the other block — this is best 
done previous to soldering down one of the blocks 
to the plate. When the tube is in position, fill the 
space between it and the sides of the holes in each 
block with white lead, and use a wire to see that 
the communication with the boiler and the glass 
tube is left quite free. Lay the gauge aside for a 




Fig. 18. 

week or two near the fire to harden. When this is 
complete, the gauge will be found perfectly steam- 
tight, will remain so, and can be attached to the 
boiler by soldering the plate all round the edges, 
having previously drilled two holes in the shell, 
through each of which one of the brass tubes passes 
when the gauge is fixed on to the boiler. 

Gauge-cocks (see Fig. 18). These are fitted to 
the boiler to ascertain the height of the water 

F 



66 



MODEL ENGINE CONSTRUCTION. 



inside, and are used instead of a gauge-glass, or in 
order to check it. For models, two are sufficient ; 
they are to be inserted so that steam should issue 
from the boiler on opening the upper cock, and 
water upon opening the lower one. These articles 




Fig. 19. 



are best purchased ready-made, as they are difficult 
to construct, and can be had from r V' bore up 
to \' and larger sizes. 

The blow-off cock is the same as the above, but 
larger, and is inserted through the shell oj)posite 
to the lowest part of the internal fire-box, and is 
used to blow off mud, scale, etc., from the boiler. 



THE BOILERS AND THEIR FITTINGS. 67 

Mud-plugs are not required for small models. 

The whistle (see Fig. 19) is made out of a brass 
casting. It consists of a bell-top with a cup-shaped 
chamber underneath, supported on a hollow stem, 
containing a cock, which can be screwed into the 
boiler. The bell-top is screwed on to a small central 
spindle, which projects upwards, being supported 
on a disc which has a narrow neck or groove, of 
a circular shape, cut underneath it. The central hole 
through the stem must be drilled up to the neck, 
but no further; then four small holes are to be 
drilled in a radiating direction from the groove 
inwards to the central hole. A brass ring is put 
on, surrounding the disc, leaving a narrow opening 
between them. This ring is screwed or soldered on 
to the stem below the groove ; the groove, being 
surrounded entirely by the ring, forms a kind of 
chamber below the disc, and when steam is turned 
on, it fills this chamber, and escaping between the 
disc and ring all round, strikes against the edge of 
the bell and produces a whistle. 

A much simpler whistle is made by taking a bit 
of brass tubing, blocking up one end, and partially 



68 



MODEL ENGINE CONSTRUCTION. 



closing the other, by soldering or screwing in a piece 
of brass rod, with a flat filed on one side. The mouth 
is made with the corner of a file on the same side 
as the flat (like an ordinary whistle), just above the 
bit of brass. The tubing is now soldered on to a 
cock, and the whole is complete (see Fig. 20). 

The clack-box (see Fig. 21) is placed just over the 




Fig. 20. 



top of the fire-box in the delivery-pipe, where it 
enters the boiler. The water enters at W, forcing 
up the valve V, and passing through the passage P 
into the boiler. Thus water passes in, but none gets 
out, as any backward flow would tend to force the 
valve more firmly down upon its seat. Only engines 
provided with a force-pump require this valve. The 



THE BOILERS AND THEIR FITTINGS. 69 

clack-box is a casting or a brass block. A passage 
must be made right through the block, of the same 
size as the delivery-pipe W. From one end take 
out a second cut from the bore, and stop short of the 
opposite end, so as to leave a collar between the 
wide and narrow parts of the bore ; this collar forms 
the seat for the valve V. To the lower end is screwed 




Fig. 21. 

a pipe or coupling-screw, which forms a junction 
with the delivery-pipe from the pump. Into the 
upper end is screwed a circular brass plug C, which 
acts as a stop for the clack V, and can be taken off 
when required to examine the interior. At the 
centre of the clack-box, on one side, drill a horizontal 
passage P (of the same bore as the delivery-pipe) 



70 



MODEL ENGINE CONSTRUCTION. 



which leads into the interior, but higher than the 
valve V can rise ; a short pipe connects the clack-box 
with the boiler. The valve V is made of brass, or is 
a casting : it consists of a disc, convex on one side, 
the other being the edge or face, which is conical. 
The conical edge of the disc must fit accurately on 
a corresponding seat formed by the collar mentioned 







Fig. 22. 



above. The valve is guided in rising and falling by 
three feathers underneath, or by a stem filed flat 
upon three sides. In large engines, the lift of the 
valve should not exceed one-fourth of the valve's 
diameter. 

The regulator. This in models is simply a cock 
screwed into the boiler, which carries a coupling- 



THE BOILERS AND THEIR FITTINGS. 71 

screw or union at its upper end, and is joined by 
this to the steam-pipe leading to the cylinder. 

A wheel-valve can be used instead, and castings 
for making this may be obtained at the model- 
makers (see Fig. 22). 

The blower is a pipe constricted at the mouth, 
and let into the funnel, having a cock placed 
between it and the boiler. When steam is allowed 
to pass through this pipe, it acts as a blast and 
intensifies the fire, causing a very rapid production 
of steam, and is used when the engine is at rest, 
and steam is low. 

The force-pump (see Fig. 23). This is used to keep 
the boiler supplied with water while the engine is 
running. It is easily made, and gives satisfaction 
even though small. We give a full-size sectional 
drawing of a pump suitable for an engine with 
a f" bore cylinder, and it will supply a boiler 
10" X 5". 

The barrel, valve-box, and plate for screwing to 
the bed-plate are all of brass in one casting. It is 
worked by an eccentric on the crank-shaft of the 
engine. When cast, reduce the casing to the sizes 



72 



MODEL ENGINE CONSTRUCTION. 



given, and finish off by boring and turning the 
barrel and the interior of the valve-box. Make the 
pump 1" x J" thick, with a J" projecting plate on 
one side ; fit a stuffing-box and gland to the mouth 
of the barrel. Make the plunger out of a piece of 
brass rod, cut a slot at one end for pivoting to the 





Fig. 23. 



eccentric-rod, turn the rest of it circular, to be an 
easy fit within the barrel ; it must be packed with 
tow in the stuffing-box, and the gland screwed up 
firmly on the packing. Next, from the upper end of 
the valve-box drill a hole fully -f^" wide, to a depth 
of \" ; bore a second hole, T y diameter, to a depth 



THE BOILERS AND THEIR FITTINGS. 73 

of J" ; and lastly drill a third hole, ^" bore, to the 
depth of \"i These holes being all continued in 
one vertical line, entrance holes for the delivery- 
and suction-pipes must be drilled into them at the 
top and bottom of the pump. The taper, which it 
will be noticed is given for a short distance to each 
of the holes by the different-sized drills, will do for 
the valve-seats. It will be seen that the delivery- 
pipe enters just above the valve-seat A, and the 
suction-pipe below the valve-seat B ; the barrel 
must be bored through right into the central aper- 
ture. The valves are two in number, made of brass 
wire and turned on the lathe. The larger is the 
delivery- valve, nearly T 5 T " across the face ; the upper 
stem is the thickest, and is left circular; the lower 
one is smaller, and of a triangular shape. A hole 
must be bored right up the centre of the stem of 
the large valve to a depth of \" ; into this hole the 
spindle of the suction-valve passes, when both valves 
are in their places, and so the larger valve regulates 
the lift of the smaller one. The suction-valve is 
the lower, and is much smaller than the other, the 
facing being nearly ■£$" diameter. The valves must 



74 MODEL ENGINE CONSTRUCTION. 

be made tight according to the method already 
described : the upper opening of the valve-box 
should be closed by a flat bit of brass, made air- 
tight, and held in position by screws. The lift of 
the upper valve is limited, by striking against this 
piece of brass, and depends on the length of the stem 
above the valve face. To insure success, make the 
delivery- and suction-pipes as short as possible, or 
in other words, have both tank and pump as near 
the boiler as convenient. 

Action. — The plunger works in and out of the 
barrel, leaving a space behind it when drawn out, 
which is supplied with water through the suction- 
pipe and lower valve, and this water, not being able 
to get past the lower valve, when the plunger is 
pushed inwards, must force its way past the 
delivery-valve, and through the delivery-pipe to the 
boiler. A check-valve ought to be placed at the 
mouth of the delivery-pipe, where it enters the 
boiler. 

The injector (see Fig. 24) is an instrument for 
supplying a boiler with water, and is used instead 
of a pump. It is made from a casting, and is very 






THE BOILERS AND THEIR FITTINGS. 



75 



difficult to fit up. A small model does not work 
well; there is difficulty with the nozzles, and the 
steam is of a low pressure : it does best with high- 



w 




pressure steam. For these reasons we pass it by, 
except giving a sectional drawing of one, and a short 
description of how it acts. Steam from the boiler 



76 MODEL ENGINE CONSTRUCTION 

is admitted by pipe S into the injector and passes 
through the nozzle N; this passage is opened and 
shut, and the amount of steam admitted through 
it controlled, by the spindle SR.W ; the steam then 
runs along the passage D, and past a check-valve 
into the boiler. By the suctional action of the 
current of steam, water is drawn in from the water- 
tank through the pipe W, and is carried with the 
partly-condensed steam through D into the boiler. 
The supply of water is regulated by the hand-wheel 
WRW ; O is the overflow-pipe. The valve-spindle 
V passes through a stuffing-box at the upper part 
of the injector. 

Fuel. Small engines should be heated by means 
of methylated spirits of wine, or a gas-burner. 
Charcoal and ordinary coal are out of the question, 
unless the boiler is tolerably large, for in small 
boilers sufficient draught cannot be got to support 
the combustion of these substances. If our readers 
must have solid fuel for their boilers, we may state 
that blocks of wood cut into sizes 1" x J", or less, 
and steeped in methylated spirits, will burn in a 
very small boiler, provided there is a grate ; but it 



THE BOILERS AND THEIR FITTINGS. 77 

requires constant stoking to keep the fire up. We 
have seen a brazed vertical copper boiler 12" x 7^", 
with an outer fire-box 7 J" x 6", which burned coal, 
and drove an engine having al" bore cylinder, and 
did fairly well. The flue-tube was 2j" diameter,, 
and about 18" long. The grate was made of a 
circular hoop of sheet-brass fitting inside the fire- 
box, across which was riveted half-a-dozen ^-" iron 
fire-bars. The whole thing rested upon brackets 
inside the fire-box. 



CHAPTER III. 

THE STEAM-ENGINE. 

The steam-engine, in whatever form it exists, 
consists of a bed-plate, which carries two distinct 
mechanisms : (1) The driving mechanism, viz. the 
piston, piston-rod, cross-head, connecting-rod, crank, 
crank-shaft, and fly-wheel; (2) the valve-gear, viz. 
the slide-valve and spindle, and the eccentric, with 
its rod and strap : these control the admission of 
steam to one side of the piston, and the exhanst 
from the other. In addition to these there may 
be other mechanisms added, viz. a governor, to 
regulate the speed, a link motion to reverse the 
engine, and a separate cut-off valve, etc. 

The Parts of a Steam- Engine. 

The bed-plate is the frame on which the engine 
rests, and is either a brass or iron casting, containing 









THE STEAM-ENGINE. 



79 



the water-tank, or a plate fixed on a wooden block, 
or supported upon turned pillars. It should be 
filed, or planed quite flat upon the top, before centre 
lines are scribed upon it, for getting the parts of 
the engine into line with each other. 





Fig. 25. 



The cylinder (see Fig. 25) is the most important 
part of the engine, and unless accurately made, the 
engine will turn out a failure under steam. It is 
a brass or iron casting (brass is the easiest to work), 
and ' unless bored by the maker when ordering — 



80 MODEL ENGINE CONSTRUCTION. 

which can be done for an extra shilling or two, 
and will save much trouble — must be done by the 
amateur himself. This is a difficult task, and re- 
quires careful workmanship to insure accuracy. The 
cylinder, instead of being cast solid, is provided 
with a cored passage running through it, about 
yV" less than the finished bore is to be. Turn a 
piece of hard wood on the lathe, drive the cylinder 
firmly on to this, and face up both ends, so that 
they are at right angles with the cored passage. 
To bore out the cylinder true, attach it to the 
lathe face-plate by means of three dogs or clamps, 

gripping the flange of one end all round. Be sure 

* 

that, when the cylinder is chucked in the lathe, 
the centre of the cored passage is in line with the 
lathe-centres. Get a steel cutter made by a black- 
smith, long enough to pass through the cylinder 
from end to end, and having four parallel cutting 
edges large enough to take out a ^-" cut. The point 
of the cutter only should have a slight taper, just 
sufficient to enter the cored passage, and the tool 
should be tempered so hard, that the cutting edges 
will remain sharp all the time while the cylinder 



THE STEAM-ENGINE. 81 

is being bored out. Insert the cutter by one end 
into the movable lathe head-stock, and by the 
other into the cored passage in the cylinder. After 
chucking, feed the cutter forwards by means of the 
hand-wheel, while the cylinder is revolving in the 
lathe ; the cutter is kept from revolving by setting 
the T-rest at right angles to the lathe-bed, and 
letting the tool slide along the top of the T-rest, 
as it advances forward into the cylinder. Do not 
stop the boring process, till the cutter has gone 
right through the cylinder, after which the bore 
will be found quite true and perfectly circular, if 
the cylinder has been properly chucked. A second 
cut can be taken by means of a rose-cutter (slightly 
tapering at the point only), while the cylinder is 
still chucked ; and after this has gone through, the 
cylinder will be found perfectly true and as smooth 
as glass inside. This second cut is not absolutely 
necessary, if the steel cutter has been well made, 
with the four cutting edges perfectly parallel to 
each other, and of a temper hardened, so as to 
remain quite sharp during the whole of the drilling 
process. A little oil can be used to facilitate boring 

G 



82 



MODEL ENGINE CONSTRUCTION. 



operations. The cylinder is now smoothed all over 
with a file, and can be painted where it has not 
been turned. It will be noticed that as yet the 
steam- and exhaust-ports have not been bored out. 
Steam-ports (see Fig. 26). In large cylinders the 
steam-ways are cast in ; in small models they must 
be drilled. Take the cylinder, square up the valve- 




Lines scribed on cylinder valve-face, where they intersect 
parts, must be drilled. 

Fig. 26. 



face, and flatten it by filing ; measure off and draw 
a vertical line through the centre. Now draw two 
vertical lines, one being on either side, each distant 
about two and a half times the width of the finished 
steam-port from this central line. Next draw a hori- 
zontal centre line, where these lines intersect each 



THE STEAM-ENGINE. 83 

other; punch three holes to form the ports — the 
middle one is for the exhaust, the outer ones for the 
admission of steam. Next mark the steam-ports on 
the face of each flange, not far from the bore ; punch 
these holes, which must be drilled in the middle 
line, of the thickness of the ridge that runs from the 
valve-face to the cylinder mouth. Fix the cylinder 
in the vice, drill the exhaust-port for a short distance 
inwards, but stop short of piercing the bore ; drill 
a hole to meet this one at right angles : this forms 
the exhaust-port. With a smaller-sized drill bore 
the steam-ways straight inwards for a short distance ; 
after this is done, with the same drill drill a hole 
from either end into each steam-way, and be careful 
not to run through them, and let the mouth of 
the drill enter the exhaust-port. Now with a small 
chisel square the ports, and prolong them vertically 
for a short distance on either side of the horizontal 
centre line. This makes the engine steam better. 
At each end cut a slot out, so as to make a steam- 
way between the ends of the port-holes and the 
cylinder bore, that they may remain open for the 
passage of steam, when the covers are bolted on. 



84 MODEL ENGINE CONSTRUCTION. 

In a J" bore cylinder the steam-ways can be drilled 
with a T y drill, and the exhaust-port with a -gV' 
drill, as the exhaust-port must always be wider 
than the steam-ports. 

The covers. These are simply circular discs of 
brass or iron which close up the ends of the cylinder. 
The front one contains a stuffing-box, and has the 
piston-rod passing through it ; but in all other 
respects it is similar to the back cover. It is best 
to fit up the back cover first, as it is the easiest. 
Find the centres, and centre punch on both sides ; 
take a long, narrow strip of sheet brass, drill a big 
hole in one end to allow of the lathe-centre enter- 
ing the central hole in the cover when chucked, 
solder this strip on to what when finished will be 
the outside, chuck in the lathe, and this brass strip 
will rest against the crank of the mandrel, and 
act as a lathe-carrier, taking the cover round with 
it. Turn the edges to the same diameter as the 
cylinder flanges; face it up truly. Some covers 
have a projecting part which enters the cylinder 
bore when in position, but this is not required. 
Now remove the cover, undo the solder, and reverse 



THE STEAM-ENGINE. 



85 



the cover in the lathe. Having soldered the strip 
of brass to the previously-turned face, turn this 
side as before, remove the strip, file off all the 
solder, and the cover is finished. A hole can be 
drilled through the centre, to screw in a lubricator 
(see Fig. 27). 

The front cover (see Fig. 28) is fitted up in the 




Fig. 27. 



same way. Drill a hole right through it, so as 
to be an easy fit on the piston-rod ; widen this 
hole for about half its depth, beginning at the out- 
side or stuffing-box end. With a plug-tap make 
a screw in it. If the hole for the piston-rod is T V' 
diameter, that for the stuffing-box should be J" 
diameter, continued for a depth of -^". Take a 
piece of brass T y long and §" diameter, bore a 



86 



MODEL ENGINE CONSTRUCTION. 



central hole T V' diameter in it, turn a piece of 
iron wire so as to fit this hole, fix the brass on it 
by soldering at one end, chuck in the lathe, turn 
a projecting flange at one end, and then turn 
down the rest, till it will tap with the same 
thread as was used for the stuffing-box ; remove the 
piece of brass from the iron wire — this forms the 



R 
% 

% 



I 







Fig. 28. 



stuffing-box gland, and can be screwed into place. 
Sometimes, instead of the gland being screwed in, 
it is held in position by two bolts and nuts, in 
which case, the stuffing-box is cast on the cylinder 
cover of an oval shape. The flange of the gland is 
also oval, and instead of being screwed up against 
the packing, the neck simply fits closely inside the 
stuffing-box, and is held up against the packing by 






THE STEAM-ENGINE. 87 

two bolts passing through its flange, which have 
nuts to keep it in place. The bolts are screwed 
into the cylinder covers. This plan is not a good 
one for small models, as it is very troublesome to 
remove the glands for re-packing. 

To fasten on the covers. Drill four bolt-holes 
through each cover near the circumference, equally 
distant from the centre, and at the same distance 
from each other ; fix the cover in its place upon the 
end of the cylinder (a little solder does well to hold 
it, and this can be filed off afterwards), mark upon 
the flange the position of one of the bolt-holes, 
insert a drill through this hole in the cover, and 
drill through or partly through the cylinder flange, 
tap a screw-thread, and insert a screw through 
the cover and tighten up (its head holding the 
cover on). Next, with the same drill bore three 
more holes in the flange, corresponding to those 
in the cover, while this latter is still in posi- 
tion, and in this way the holes must be correct, 
and correspond with the holes drilled through the 
cover; put in three more screws, and tighten up. 
If a little red lead is put in between the faces, 



88 MODEL ENGINE C0N8TEUCTI0N. 

this will make the joints quite steam-tight. A flat 
india-rubber ring put in between the cylinder flange 
and cover, if the latter is tightened up on it, keeps 
the parts steam-tight; but a bit must be cut out 
of the ring previously, which corresponds to the 
position of the steam-port, to leave this uncovered 
for admission of steam to the cylinder. This plan 
does for large models. Small bolts may be screwed 
into the cylinder flanges, the covers made to slip 
over them, and be tightened up against the cylinder 
with nuts. Bolts and nuts are used in large engines 
for holding the covers on. 

The front cover is fastened on to the cylinder 
in the same way, but before drilling holes through 
the cylinder flange to correspond with those in the 
cover, the piston must be finished, packed with -tow, 
and placed in the cylinder, with its rod passing 
through the gland, screwed up tight in the stuffing- 
box. Push the cover up against the cylinder face, 
when it will be found that the stuffing-box is in 
line with the bore; and if corresponding holes be 
now drilled in the cylinder face and the cover 
bolted on, the piston will work quite easily back- 



THE STEAM-ENGINE. 89 

wards and forwards, if not packed too tight — a little 
oil is a great help to lessen friction. — 

The steam-chest is a separate casting, flat on the 
outside, with a projecting part which, when bored 
through, will form the steam inlet. The inside is 
hollow, and is surrounded by a square flange, which 
is bolted to the valve-face; the front has a pro- 
jecting part also, which is to form the slide-valve 
stuffing-box. The inlets for the steam and the 
stuffing-box only require turning; the other parts 
are to be filed up smooth and square. If the 
inside is very rough, it may be smoothed down by 
taking pieces out with a small chisel (when gripped 
in the vice), so as to give plenty of room for the 
travel of the slide-valve. Fit up the stuffing-box 
and gland as already mentioned. Drill the inlet for 
the steam, and tap the hole for screwing in the 
steam-pipe. Drill four bolt-holes through the chest 
near each corner, and widen these with a rimer; 
place the chest in position against the valve-face 
of the cylinder, drill a hole at each corner, and 
attach the cover with bolts and nuts, following the 
directions given for the cylinder covers. Be careful 



90 MODEL ENGINE CONSTRUCTION. 

that the ehest is attached in such a way that, when 
the piston-rod and valve-rod are in position, they 
remain parallel with each other. The chest is held 
in position by four nuts, and is made steam-tight 
by red lead or india-rubber. 

Where the exhaust-port opens out above the 
cylinder, the mouth should be widened with a 
rimer, to a depth sufficient to take a screw-thread ; 
it may then be tapped, and the exhaust steam- 
pipe screwed in, which ought to be of a rather 
larger bore than the steam-pipe. It is a good 
plan to screw a lubricator and cock into the 
upper part of the slide-valve case, in order to 
lubricate the slide-valve, for if well oiled it works 
more easily. 

Pet-cocks are employed at each end of the cylinder 
to let out the water that condenses, when steam is 
admitted to a cold or partly-cooled cylinder. They 
are screwed into two lugs, which are cast upon the 
inside of the flanges, it may be on the under sur- 
face. Holes must be drilled through into the bore 
of the cylinder before screwing in the cocks; both 
cocks may be connected together by a rod, so that 



THE STEAM-ENGINE. 91 

they can act together. In small models these are 
unnecessary, except for the sake of appearance. 

Horizontal cylinders are fastened to the bed-plate 
by means of bolts passing through feet or lugs 
cast upon them (see sketch), or by bolting them to 
the front covers, which are cast on the bed-plate. 
Vertical cylinders are bolted through the covers 
to the top or bottom of the frames that support 
them. 

A lagged cylinder is one with strips of wood 
resting on the flanges, fitted together and held in 
place by two metal bands, leaving a space around 
the cylinder which may be filled in with felt, or 
some non-conducting material, as hair. Lagging 
need not be applied to small cylinders, as it is 
troublesome to fit on properly. Its use is to prevent 
radiation, and render the cylinder hotter. 

The piston. In small engines this is simply a 
circular brass disc, with a groove to hold the pack- 
ing. The piston must be turned quite circular, be an 
exact, yet an easy fit in the cylinder. It is screwed 
to one end of the rod which passes through its 
centre. For small engines it is impossible to turn 



92 MODEL ENGINE CONSTRUCTION. 

the piston upon the rod in the lathe, as we do when 
making the larger sizes ; so it is best to drill the 
piston through the centre, fasten it by solder upon 
a temporary shaft (of iron wire) fixed between the 
lathe-centres, and after turning, it will be found to 
be perfectly circular, and the hole passing through 
it coinciding with the centre. A piston suitable 
for a §■" or J" bore cylinder should be made \" 
broad, having a •§•" groove for packing, with a T V' 
collar on each side of it. If these pistons are 
properly packed at first, they will give very little 
trouble afterwards, as the collars prevent the pack- 
ing from being blown off by the steam. The 
narrow pistons found in cylinders purchased in the 
shops, with a T V' groove and a narrow (j%") collar 
on each side, after being run by steam once or 
twice become useless, as the packing gets blown 
off if the pressure is at all strong. The piston is 
made steam-tight by packing with hemp or tow, 
well saturated with oil or melted tallow. After 
packing, work the piston backwards and forwards 
by hand in the cylinder till it goes easily. Pistons 
must never be made a tight fit. 



THE STEAM-ENGINE. 93 

In large models and small-power engines, the 
piston is an iron casting composed of two separate 
pieces : the piston proper, and a circular disc which 
goes behind it, the "piston follower." Turn the 
piston-rod out of a piece of steel or iron wire, centre 
both the piston and follower, centre punch and drill 
through, screw them both on to one end of the 
piston-rod (this part of the rod being turned down 
narrower where it enters the piston, so as to leave a 
collar against which the piston can be tightened up). 
A little piece of the rod should project at the back 
through the piston for a nut to tighten the piston 
up against the collar; chuck the piston-rod and 
piston in the lathe, then turn and face the piston 
while revolving on the piston-rod; turn the piston 
just a shade less than the bore of the cylinder. To 
render this size of piston steam-tight, one, or it may 
be two, brass or iron rings are made to surround 
it called " piston-rings," and to get them over the 
piston the follower must be removed from the 
piston-rod. In large engines the piston-rod is 
tapered where it passes through the piston. 

Piston-rings (see Fig. 29). The ring is an iron or 



94 MODEL ENGINE CONSTRUCTION. 

brass casting. File the inside of the ring with a 
round file, to fit the groove on the piston. In order 
to turn the ring, turn a piece of hard wood and drive 
the ring firmly on to it with a mallet, chuck this in 
the lathe, and turn the ring to a size a little larger 
than the cylinder bore; face the ends. Next put 
the ring in the vice, gripping it at the sides with 
a fine drill, drill three or four holes through it 



v//////////A ~l>/ ////////m 



m 



W=^rzz^r~#^l^-^^2r 




Fig. 29. 

lengthways in the circumference, close to each other. 
With the frame-saw make a cut from the edge right 
through to the first hole; do the same from the 
opposite side to the last hole in the row, give a tap 
with a chisel, and the ring will split open ; file the 
edges of the cut smooth, and bring them close 
together by filing, so that by compressing the ring 
tightly with the hand it will enter the cylinder. 
Place the piston in the cylinder (having removed 



THE STEAM-ENGINE. 95 

the follower), and by compressing the ring it will 
slip over the piston; place the follower in position, 
tighten up the nut, and it is finished. The spring 
of the ring against the cylinder keeps the piston 
steam-tight. The elasticity can be increased by 
hammering the ring all round upon the inside with 
a light hammer, while it is resting on a block of 
wood, before placing it on the piston. One ring 
will do for models. Making the "split" according 
to the above method causes less escape of steam 
than if the ring be simply sawn across. When two 
rings are used, they are placed upon the piston so 
that the split occupies different sides. 

The piston-rod is made of steel or iron wire turned 
on the lathe, and of such a length that when the 
piston is close up to the back of the cylinder, or on 
the "inner dead centre," the cross-head keeps clear 
of the stuffing-box. Their diameters range from 
one-sixth to one-tenth the diameter of the cylinder 
bore in actual practice. The rod is made steam- 
tight where it passes through the stuffing-box by 
means of tow or hemp, and the gland is tightened 
up on the packing as required (see Fig. 29). 



96 MODEL ENGINE CONSTRUCTION. 

The cross-head is a cast brass or iron block, screwed 
to the end of the piston-rod, and forms the junction 
between the piston-rod and the connecting-rod, by 
means of the cross-head pin, which is screwed into 
it. The head is either slotted out at the end to take 
the connecting-rod, or the latter is forked, in which 
case the head is solid. Projecting pieces are cast 
on the top and bottom, which must be smoothed ; 
these work on the guide-bars, and thus guide the 
motion of the piston-rod. These guides, instead of 
being cast on, may be separate, simply flat blocks 
of brass with a shoulder inside, and into the centre 
of which the cross-head pin passes, after passing 
through the cross-head, and these " guides " or " slip- 
pers " slide along between two parallel guide-bars on 
each side, one above, and one below. 

The guide-bars should be an easy sliding fit for 
the cross-head " slippers." They must be set truly 
in line with the axis of the cylinder bore, so as to 
guide the piston-rod when travelling in a straight 
line. They must be filed smooth all over, and the 
guide surfaces made quite flat. The lower guide 
bars are bolted at each end to the bed-plate; the 



THE STEAM-ENGINE. 97 

upper bars are bolted to the lower ones, washers, 
or distance-pieces, being inserted between them. A 
small hole is drilled in the centre of the upper bars 
for oil, or an oil-cup can be screwed in. Instead of 
this, there may be four brass pillars, each having 
a lug for attaching the bars to ; these pillars are 
bolted to the bed-plate, two on either side of the 
piston-rod. The bars are made out of a piece of 
iron filed flat, each cut to the same length, drilled 
at both ends, and fastened by bolts, passing through 
the lugs in the pillars. In this case, the " slippers " 
must be filed down, so as to be an easy fit between 
the bars. The pillars must be fixed to the bed- 
plate on each side, so that they keep clear of the 
cross-head guides, when the piston is on the dead 
centres, or in other words, that the guiding surface 
must be longer than the stroke. 

In vertical engines the cross-head simply slides 
up and down between the frames, being kept in 
place by a groove, cast upon opposite sides of the 
guide-frames. 

The connecting-rod (see Fig. 30) is made of soft 
iron, cut to the proper length, circular or square, but 

H 



98 



MODEL ENGINE CONSTRUCTION. 



having the ends flattened, the crank end being the 
larger of the two, and in its simplest form is just 
this, with the addition of a hole drilled through at 
each end, one for the cross-head pin, and the other 
for the crank-pin ; but so simple a rod as this is not 
very " engine-like," and besides, with a centre crank, 
it could not be got over the crank-pin. On the 



c 





o 



UDOK 



3ZD 



Fig. 30. 



other hand, a correctly-modelled connecting-rod, 
brass bushed, with jib and cotter for tightening up 
the brasses, would be very difficult for an amateur 
to construct in such a small size, so we describe 
and illustrate a form of rod of the " marine type," 
which is tolerably correct, and if well finished has 
a good appearance. Get a blacksmith to forge a T- 



THE STEAM-ENGINE. 99 

shaped piece of iron, centre punch, and turn it on 
the lathe, tapering slightly towards each end. The 
cross-head end is solid ; file it circular at the end, 
and bore it out for the pin ; or this end may be 
forked. Drill two bolt-holes through the T-shaped 
head, at equal distances from the centre, smooth 
and flatten a piece of brass, of the same thickness 
as the end, drill two holes through this to corre- 
spond with those in the T-head, put on a flat piece 
of iron at the end — this gives a better finish. With 
a frame-saw, saw the brass longitudinally through 
the centre, take off the rough cuts with a file, make 
two bolts and nuts, pass the bolts through the brass 
and the strip of iron in front of it, and bolt on 
to the T-head. This end of the connecting-rod is 
finished, and contains the " brasses," and is ready 
to be drilled for the crank-pin. Centre, and punch 
a hole, then drill so as to make the hole an easy 
fit on the crank-pin, and it will be found that half 
of the hole just drilled is in one brass, and half in 
the other. After polishing, remove the bolts, slip 
the crank-pin through the brasses, tighten them up, 
and the connecting-rod is complete. There are no 
L.rfC. 



100 MODEL ENGINE CONSTRUCTION. 

means of adjusting the brasses for wear, but this is 
practically nil in a model engine. 

The connecting-rod is usually made six times the 
length of the crank, or it may be made two and a 
half times the length of the stroke. 

Bearings and plummer-block (see Fig. 31). This is 
a casting, having a sole for bolting to the bed-plate. 




Fig. 31. 

File it all over, and make the under surface of the 
sole that rests on the bed-plate perfectly flat and 
true, or else it will rock when the engine runs. 
Drill bolt-holes into each end of the sole, widen 
these with a rimer, so that they will pass easily 
over the bolts, screwed into corresponding holes in 
the bed-plate ; when fixed, the plummer-block is 
retained on the bolts by nuts. From the top 
of the bearings drill two holes (near the ends) 



THE STEAM-ENGINE. 101 

downwards, about half the depth of the plummer- 
blocks, bolt down both bearings to the bed-plate 
(having previously bolted down the cylinder), mark 
on the outside of each a horizontal line, which 
exactly corresponds to the horizontal central axis 
of the cylinder (this is done to get the engine 
fitted truly " in line "). Make a saw-cut horizontally 
through this line in both bearings, the detached 
piece forms the cap, or upper half of the " brasses " ; 
widen the vertical holes in this with a rimer, so 
that they will easily slip over the bolts, screwed into 
the plummer-block, and be tightened up by nuts. 
Mark the centre of the saw-cut in both. Drill a 
transverse hole through each, of such a size as 
allows the journals of the axle room to revolve 
freely inside, then drill a small hole through the 
cap for oil. 

Note. — Bearings should be fixed to the bed-plate, 
so that the crank-shaft is at right angles to the 
piston-rod, and exactly in line with it, when the 
cylinder is bolted down in position. 

Standards for vertical engines are fitted up in 
the same way, and must be so bolted to the bed- 



102 



MODEL ENGINE CONSTRUCTION. 



plate, that the central axis of the crank-shaft will 
stand vertically over the centres of the piston-rod 
and eccentric-rod. In an ordinary steam-engine, 
each plumroer-bloek is an iron casting, having a 
sole, through which pass the holding-down bolts ; 







Fig. 32. 



the cap is also a casting. Between the block and 
the cap is fitted the brass bush to take the axle. 
This bush is in two halves, which are called the 
"brasses" or " steps"; these are cast with flanges 
on both sides to keep them in position, and to 



THE STEAM-ENGINE. 103 

prevent them turning along with the axle. They 
are furnished with lugs, which enter corresponding 
recesses in the block and cover (see Fig. 32). 

The crank-axle (see Fig. 33), by means of the 
crank, converts the reciprocating, to-and-fro motion 
of the piston into a circular motion, through the 
intervention of the piston-rod and connecting-rod. 
When the crank is set at one end of the shaft, 
it is called a "single crank." When there is a 




n 



Fig. 33. 

bearing on both sides of the crank-webs, it is called 
a "centre crank." 

Note. — Whatever form is adopted, the crank-web, 
or distance from the centre of the axle to the 
centre of the crank-pin, must exactly equal half 
the distance of the stroke. 

The single crank is easiest to make. Take a 
piece of iron wire (the proportion of the shaft is *33 



104 MODEL ENGINE CONSTRUCTION. 

of the diameter of the cylinder), cut to the proper 
length, chuck and turn in the lathe, turn down 
to a smaller diameter, the parts which form the 
journals, then screw the shaft to the crank- web. 

To make the web, take a piece of brass, at the 
proper distances to suit the length of stroke, drill 
two parallel holes straight through the web, screw 
the end of the shaft tightly into the largest hole, 
and into the other hole screw the crank-pin, till the 
shoulder bears on the web (as the part that enters 
the web is of a less diameter than the rest of the 
pin). All the joints may be soldered as well as 
screwed, to make them strong. 

A centre crank (see Fig. 34). In these days of 
cheap castings and forgings, the best plan perhaps 
will be to buy a solid, unfinished bent steel crank- 
shaft, as sold by the model-makers. This can be 
turned and finished on the lathe, and when finished 
will prove far stronger than a built-up crank-shaft. 
They are sold in sizes ranging from a \" throw up to 
small-power sizes. 

A built-up crank-shaft is made as follows. We 
assume that the axle has been turned, accurately 



THE STEAM-ENGINE. 105 

measured, cut to the proper length, the journals and 
crank-collar turned. Take two flat pieces of brass 
(for the webs), make them of the same length, mark 
and centre punch holes at the distances to give the 
proper throw. Be sure the holes are drilled straight 
through each web ; the widest hole at one end is for 
the crank-shaft to pass through, the narrow hole at 
the other end is for the crank-pin. Take a piece of 
wire for the crank-pin, file down a bit at both ends, 




Fig. 34. 

leaving a shoulder, screw both shoulders firmly into 
the webs, and if the holes have all been carefully 
bored and centred, the axle will run perfectly true, 
when placed in the lathe. The crank-pin does not 
require turning, but the corners can be taken off the 
crank-webs with a file. Solder the parts together. 

The fly-wheel is a brass or iron casting, contain- 
ing five or six spokes. Take the wheel, centre it 
accurately upon both sides, and punch the centre 



106 MODEL ENGINE. CONSTRUCTION. 

holes ; then drill half-way through from both sides 
of the central boss ; the hole must be a sliding fit 
on the crank-axle. Turn a piece of wire, to be a 
tight fit in the wheel ; with a mallet drive the wheel 
on to it, attach with solder if required, and chuck 
in the lathe ; turn and face the wheel. The 
diameter is generally made about four times the 
stroke. Remove the wheel from the lathe, and file 
the inside of the rim and spokes smooth ; these can 
be painted afterwards. In the lathe, the fly-wheel 
might be turned on its axle, but a small fly-wheel 
is best turned upon a temporary axle, from fear of 
bending the axle in any way. The wheel is attached 
to the axle by screwing, soldering, or keying on. In 
this last case, the shaft must be filed away a little 
on one side, so as to be flat over the fly-wheel seat ; 
with a fine file, a small recess or key-way must be 
cut in the boss of the wheel. When placed in 
position, this recess in the wheel must correspond 
to the flat or key-bed on the shaft ; a small wedge- 
shaped key is driven into the space between the 
wheel and the shaft, and the wheel will now revolve 
quite true with the axle. 



THE STEAM-ENGINE. 



107 



The pulley-wheel is a brass or iron casting, fitted 
up in exactly the same way as the fly-wheel. It is 
placed upon the opposite end of the axle to the fly- 
wheel ; sometimes it is provided with a groove. 

The slide-valve (see Fig. 35) is a brass or iron 
casting, which must first be filed up square and 
smooth all over ; then with a small steel chisel — 






'/ -L^y^^j 




Fig. 35. 



while the valve is gripped in the vice — cut or hollow 
out the interior, until it becomes box-shaped, and 
having edges all round. The length on the face, 
from the inside of one flange to the inside of the 
other, should be just a shade less than the distance 
between the inner edges of the steam-ports, and the 
flanges must both be left of the same thickness at 



108 MODEL ENGINE CONSTRUCTION. 

the ends. When finished, the length of the valve 
should be such that when it is placed on the 
cylinder face in " mid-position," i. e. equally covering 
both steam-ports, its edges will extend a very little 
way beyond the ports at each end. The amount 
which the valve projects over the steam-port on the 
outside is called the outside lap of the valve, and 
the amount which it projects on the inside is called 
the inside lap. We may disregard this latter term, 
and when " lap " is used, we mean outside lap only. 
By means of "lap" an earlier cut-off of steam 
is obtained during the piston stroke than would be 
got without it. (Very small models will work well 
enough without the valve having any lap.) The 
valve-face must be filed (or scraped) quite flat. 
This is best done by rubbing the valve, with its face 
downwards, upon a flat file, laid upon the bench; 
do the same with the cylinder face, then grind both 
of them on the face-plate with emery powder and 
oil. Lastly, do the same, grinding the one upon the 
other : when completed, the valve ought to be quite 
tight on the chest. To test, wet the valve and 
cylinder face with water or oil, place the valve in 



THE STEAM-ENGINE. 109 

mid-position (holding it tightly up against the 
cylinder face), and attach a piece of rubber-tubing 
to the blast-pipe soldered into the exhaust outlet. 
On blowing through the tube, no air should pass, or 
bubble out at the sides of the valve. Block up the 
inlet and outlet of the cylinder bore, move the valve, 
so that the back steam-port and exhaust-port com- 
municate alternately; then, on blowing through the 
exhaust-pipe in either of these positions, if the 
valve is held up tightly, no air passes out at the 
sides. The valve is secured to the valve-spindle by 
nuts screwed on the spindle. These retain the 
slide-valve, as a sliding fit between them, and in 
order to keep these nuts in position on the screw, 
jam-nuts are used at both ends, so that there are 
four nuts in all, two in front, and two behind. The 
longitudinal hole through the body of the valve, for 
the spindle to pass, is made of an oval shape, to 
allow the valve to adjust itself, so as always to press 
against its seat. In small models, instead of using 
nuts, it is easier to make a longitudinal saw-cut 
along the back of the valve, and file down a piece of 
the valve-spindle quite flat, leaving a collar at each 



110 MODEL ENGINE CONSTRUCTION. 

end. Slip this part into the saw-cut, the collars 
hold the valve in place, and the saw-cut allows 
adjustment of the valve to its seat. The recipro- 
cating movement of the slide-valve is derived from 
the circular motion of the centre of the eccentric- 
pulley, through the intervention of the eccentric- 
strap, the eccentric-rod, and the valve-spindle. 

The valve-spindle is made of iron wire, turned 
circular, about half the thickness of the piston-rod. 
One end is attached to the valve, as mentioned above, 
and the other end is screwed into a block, which 
by means of a pivot, unites with the eccentric-rod ; 
the spindle passes through a steam-tight stuffing- 
box and gland. In large engines, there is a guide to 
keep the slide-valve in a straight line ; but this is 
not absolutely necessary in small models, the stuffing- 
box and gland being sufficient for this purpose. 

The eccentric-rod is an iron wire, circular or 
flattened, screwed at one end into the eccentric- 
strap, and at the other end having a hole passing 
through it for the spindle-pin ; instead of this, 
however, it may be forked at this end. 

The eccentric-strap is a brass casting, either cast 



TEE STEAM-ENGINE. 



Ill 



in two halves, or if solid, it must be equally halved 
by a saw-cut, going right through the centre of the 
hole or aperture cast in it, entering and coming out 
in the middle of the lugs, through which the bolts 
pass. It must be filed smooth all over, and, with a 
round file, the inside of each half filed out, until it 




Fig. 36. 



accurately fits upon the eccentric-pulley, when the 
two halves are brought together, and yet allow the 
eccentric to revolve freely inside. After fitting, drill 
a hole through each lug and pass two bolts through, 
which are tightened up with nuts ; a small hole can 
be drilled, and an oil-cup screwed in for oiling the 
eccentric-pulley (see Figs. 36 and 37). 



112 



MODEL ENGINE CONSTRUCTION. 



The eccentric-pulley is a circular brass casting, or 
is turned out of a bit of brass rod : the former is 
adopted for the larger sizes. This has a groove 
cast around the circumference, as well as a tenon or 
projecting boss attached to one side, for the purpose 
of gripping it in the lathe-dog when chucking ; the 
other side has, sometimes only, a second boss cast 




Fig. 37. 



upon it, made to correspond with the centre of 
eccentricity, and is for the purpose of enabling the 
eccentric to be fixed to the crank-shaft by means 
of a set-screw, passing through it at right angles to 
the shaft. If there is no boss, the eccentric must 
be fixed to the crank-shaft by means of a key, and 
a key- way must be cut out with a small trian- 
gular file. In real engines eccentrics are keyed to 



TEE STEAM-ENGINE. 113 

the shaft. To turn the eccentric, chuck it in the 
lathe, smooth the flanges, clean out the groove, and 
face up the sides. After turning, saw off the chuck- 
ing tenon, and file the edges of the saw-cut quite 
flat, lay the eccentric on a flat table or board (if 
there is no boss) with that side up, having the true 
centre marked on it (the other centre is lost by 
cutting off the tenon) ; measure, from this centre, a 
distance equal to half the travel of the slide-valve 
across the port face, mark the place with a pair of 
compasses (having their legs fixed by a set-screw), 
punch a hole over this mark — this is the centre of 
eccentricity, and a hole must be drilled right through 
the eccentric, which shall remain quite parallel with 
the centre of the true axis of the eccentric, or in 
other words, with that of the crank-shaft. If there 
is a boss, the pattern should have been so carefully 
made that the centre of this boss will exactly coin- 
cide with the centre of eccentricity, then this centre 
is easily found. To bore the eccentric, for the axle 
to pass through, is rather difficult, so as to keep the 
hole quite true ; but can be readily done, if the 

amateur possesses an upright vertical bench drill, as 

i 



114 MODEL ENGINE CONSTRUCTION. 

all he has got to do is to lay the eccentric flat on 
the bed, keep it so, choose the proper-sized drill, 
and bore out there and then. If only a hand-drill 
is his, then the eccentric must be fixed in the vice, 
and bored as straight through as possible ; a small 
round file will help to bring the hole back " true," 
if it should be a little off, i. e. not quite parallel 
with the true axis of the eccentric; if it was left 
so, the eccentric when put on the crank-shaft would 
wobble, and catch against the eccentric-strap : it 
must run dead true when on the shaft. The 
hole drilled must be just so large, as to allow the 
eccentric to slide along the crank-shaft. If there be 
a boss, it can be turned by mounting the eccentric 
on a temporary shaft in the lathe, or it may be 
smoothed over with a file. The key- way should 
always be cut in the eccentric opposite the part 
where the metal is thickest. The throw of an 
eccentric is the distance between the centre of the 
crank-shaft and the centre of the eccentric-pulley. 
The latter form of pulley (for small engines) is 
turned either singly, or in pairs, out of brass rod, 
and sawn apart. An eccentric, -J- J" diameter over 



THE STEAM-ENGINE. 115 

jail and J" wide, should have a groove T y deep 
and -J-" wide, with T y collars on each side. In 
order to insure the hole being quite true (for the 
crank-shaft) that passes through, find the centre of 
eccentricity on one side and punch the hole ; place 
the eccentric in the lathe, with the dead-centre 
point entering the punched hole, bring up the live- 
centre point so as just to touch but not mark the 
eccentric, turn the lathe slowly round, and the 
eccentric will tend to revolve between the centres ; 
if it does so, keeping at right angles to the central 
axis of the lathe-centres, and does not wobble, it is 
right. Then screw up the live-centre, so as to make 
a mark at this part, remove and punch a hole on 
this mark, fix the eccentric in the vice, drill by 
hand, or on the lathe, through half-way from each 
side, meeting at the centre. The hole thus drilled 
must be true, if properly done; if it should be a 
little way off, though only fully \" diameter, it may 
be made true, by passing through it a small round 
jewellery file, such as is used by watchmakers, and 
filing out where required. The eccentric is attached 
to the crank-shaft by means of solder, or a boss 



116 MODEL ENGINE CONSTRUCTION. 

for a set-screw can be made and soldered on upon 
one side. 

In addition to the eccentric-strap mentioned 
above, we will describe another kind which can be 
adopted for small engines, especially locomotives, 
with very good results. To make it, take a piece of 
thin sheet brass, cut a long narrow strip from it, 
much longer than the circumference of the eccentric- 
pulley, and of a width that will be an easy fit in the 
groove of the pulley. A short distance from one 
end, bend the brass at right angles, so as to form 
a lug, then mould the rest circular, to the same 
diameter as the pulley, for rather less than one- 
quarter of its circumference, and with a pair of 
pliers make a small loop on it (see Fig. 38), and 
from this loop continue moulding the circle to the 
same diameter as before. When the circle is com- 
pleted, bend the remainder of the strip at right 
angles, and cut off short, to form a lug. In this way, 
there are two lugs formed at the top of the strap 
which, when in position on the pulley, lie against 
each other, and through these the bolt passes 
for holding the strap on the pulley. Drill a hole 



THE STEAM-ENGINE. 117 

through the middle of the loop, take the eccentric- 
rod, screw two nuts on to one end, remove these, 
solder one nut inside the loop, screw the other 
nut on to the eccentric-rod, leaving an end, which 
must be passed through the loop, and firmly screwed 
into the nut soldered inside it. Screw the other 
nut upon the rod up firmly against the loop, and 
these two nuts jam each other, and hold the rod 
quite tight in its place on the eccentric-strap ; a 
little solder will also help. Or (instead of nuts) 
the rod can be put through the loop and soldered 
with hard solder. This form of strap is much 
lighter than a casting, and as the loop prevents the 
strap from rubbing at every part upon the eccentric- 
pulley, it works with very little friction, and does 
well for small locomotives, where saving of weight 
and friction is a great matter. The strap has a good 
deal of spring in it, and when the boLjb is removed 
slips very readily off the eccentric-pulley. This 
strap must be made quite circular and a good fit on 
the pulley, for, with a loop at one end, there is apt 
to be some play antero-posteriorly on the pulley, 
which it must not have. To fit it on properly, turn 



118 



MODEL ENGINE CONSTRUCTION. 



a piece of hard wood to the same diameter as the 
eccentric-pulley at the bottom of the groove, tighten 
up the strap with the bolt, and pass the strap over 
the end of the piece of wood. After removal from 
the lathe, with pliers tighten the loop, till the strap 
becomes an easy fit on the wood, and quite circular. 




<=dB==SEt » 



Fig. 38. 

Eemove the strap, take out the bolt, slip it over the 
pulley, and tighten up the bolt, with the nut, when 
the strap will be found an exact fit on the pulley, 
and its action on the slide-valve perfect. It can be 
filed slightly all round on the inside, with a round 
file, as this makes it work more easily (see Fig. 38). 
Oil-cup. This is a casting, or else is turned and 
bored out of a piece of brass rod, and screwed into 



THE STEAM-ENGINE. 



119 



its place (in a hole drilled to receive it) on the 
guide-bars, bearings, connecting-rod ends, etc. Those 
for the cylinder, with single or double cocks, had 



<s> 






f=~\ 


m 




( 


\ 




2~ < 







IA 




Fig. 39. 

best be purchased ready made, as the accurate fitting 
of cocks is troublesome. 

The governor (see Fig. 39) is a device for regu- 
lating the speed of the engine. Different kinds 
are used; perhaps the easiest to make is the 
" throttling-governor." It consists of two balls 
suspended from the top of a vertical revolving 



120 MODEL ENGINE CONSTRUCTION. 

spindle by jointed rods, which revolve with it. 
When the engine runs, they revolve at a certain 
distance from each other, and if the speed increases, 
the centrifugal force causes the balls to fly further 
apart, and, in so doing, they raise a lever which 
partially closes a circular disc of metal called the 
"throttle-valve," which, by partially shutting off 
the steam, as it passes to the cylinder, checks the 
speed of the engine. Castings for making this 
can be purchased, and by referring to the drawing 
there can be little difficulty in fitting them up. 
The frame is filed up smooth and flat; it is bolted 
by means of feet to the bed-plate or slide-valve 
casing. A vertical hole is drilled through the top 
to allow the spindle to pass, which is tapered at the 
foot, and rests in a small hole drilled in the bed- 
plate, so as to keep it vertical. Sometimes a small 
bevel tooth-wheel is fixed on this spindle, between 
the legs of the frame, and gears with another tooth- 
wheel, fixed on a spindle at right angles, which 
passes through a bearing in one leg of the frame, 
and carries a small pulley outside. An easier plan 
than this is to turn a small pulley, and fasten it by 



THE STEAM-ENGINE. 121 

soldering or otherwise to the vertical spindle ; this 
pulley is horizontal, and is driven by a band from 
the crank-shaft. The opposite end of the spindle 
carries a brass cap, firmly screwed to it, having a 
projecting lug on either side. We must now turn 
the balls and their spindles on the lathe, and slot 
a piece out of the free end of each spindle, and 
pivot a ball to each lug. The sleeve is simply a 
piece of brass, which can slide up and down on the 
spindle ; this carries two small lugs at the top, one 
on each side, and underneath these is a kind of 
pulley with a broad groove forming a collar (this 
sleeve must be turned on the lathe) ; two forked 
rods or links are pivoted to the lugs of the sleeve 
at one end, and, by means of the forks, embrace the 
governor arms about the middle of their length, and 
are pivoted to them. A long brass rod must be 
pivoted to a bearing at its centre, so that the forked 
end engages with the sleeve-pulley, and is raised 
and lowered by it ; the other end is pivoted to a 
lever connected with the crank of the throttle-valve. 
The throttle-valve is a brass disc, turned circular, 
so as to fit its case, left thickest at the centre, in 



122 MODEL ENGINE CONSTRUCTION, 

order to be drilled, and fixed upon a central hori- 
zontal spindle, by means of a small set-screw. The 
inner end of this spindle is supported in a round 
hole drilled in the pipe, whilst the outer end pro- 
jects through a steam-tight stuffing-box and gland, 
soldered into the opposite side of the pipe. Outside, 
a small crank is attached to this end, which is 
worked by rods from the governor-sleeve. When 
the throttle-valve is closed, as when the balls hang 
nearly vertically downwards, the valve bears all 
round on the inside of a short piece of pipe or 
casing, which has been bored out truly cylindrical. 
This casing must be screwed or soldered between 
the steam-cock or stop-valve and the slide-valve 
chest. When the governor has been bolted down 
in position, and a small pulley been rigidly fixed 
on the crank-shaft, a piece of cord or string is 
passed from this pulley to the governor-pulley and 
tightened up ; then when the crank-axle revolves, 
the governor will revolve, and cause the balls to fly 
apart, and open the throttle-valve. 

The governor is rather a complicated piece of 
mechanism to construct, and may be omitted in 



THE STEAM-ENGINE. 123 

engines of less than If" bore cylinders. For this 
size, the balls may be of iron, f" diameter, and arms 
3" long, of T V" iron, with a coiled spring on the 
spindle to push down the sleeve. The spindle may 
be T V" to £" thick; the spring must be chosen 
according to the speed adopted ; the pipe that holds 
the throttle-valve may be made x y to |" diameter 
inside. 






CHAPTER IV. 

FITTING UP THE ENGINE, AND SETTING THE SLIDE- 
VALVE. 

Now that all the different parts of the engine 
are finished, we must fit them together, and in 
order to show how this is done, we will suppose 
we are going to make a horizontal engine. 

The cylinder stuffing-box must first be packed, 
to render it steam-tight, and to do this the gland 
should be unscrewed, and a small piece of tow, 
soaked in oil, wound twice or thrice round the 
piston-rod between the stuffing-box and the gland, 
and pushed into the former with a wire, and the 
latter screwed firmly up on the packing to compress 
it, and given a turn backwards to make the piston 
go more easily. Work the piston backwards and 
forwards by hand, using plenty of oil, and it will soon 






FITTING UP THE ENGINE, ETC. 125 

work quite easily; pack the slide-valve stuffing-box 
in exactly the same way. Take the bed-plate, which, 
if it has been purchased from the model-maker's, 
will have the positions of the various parts marked 
upon it ; but if not, you must set out the positions 
of the cylinder, guide-bars, plummer-blocks, etc., 
from working drawings, which in the case of small 
models could be drawn to full size. The cylinder 
feet or lugs must be filed flat, and drilled for the 
bolt-holes ; the position of these holes must be 
accurately marked on the bed-plate, and drilled for 
screwing in the bolts, and the holes in the cylinder 
feet should be widened with a rimer, so as to pass 
easily over these bolts, and then the cylinder is 
fixed by nuts to the bed-plate. Be sure that the 
cylinder is filed perfectly flat on the bed-plate, and 
that it is so placed, that the piston-rod is perfectly 
parallel with the bed-plate when fully pulled out. 
Holes must be bored in the ends of the guide-bars, 
and corresponding ones made in the bed-plate, at 
the proper distance from the cylinder corresponding 
with the stroke, the two sets of bars having the 
piston-rod truly in the centre between them ; bolt 



126 MODEL ENGINE CONSTRUCTION. 

these firmly down to the bed-plate, the nuts being 
underneath. See that the cross-head and its "slip- 
pers " slides easily along between the top and bottom 
bars. The crank-shaft should be placed in the bear- 
ings, and these laid on the bed-plate. The shaft 
must be set at right angles to the piston-rod : mark 
the position of the bolt-holes, which pass through 
the soles of the plummer-blocks, upon the bed-plate, 
drill these and bolt the plummer-blocks firmly 
down; attach the connecting-rod to the crank-pin, 
by taking out the bolts from the " big end," 
removing one of the brasses, and slip it over the 
crank-pin ; put on the " step," and tighten up the 
bolts. Remove the back cover from th3 cylinder, 
push the piston back till it just touches the 
edge of the steam-port, turn the crank round, 
until it is nearest to and fair in line with the 
cylinder, or upon the "inner dead centre," mark 
on the loose end of the connecting-rod the position 
of the cross-head pin, remove the connecting-rod 
from the crank, and drill a hole corresponding 
with this mark, to be an easy fit on the pin. As 
mentioned before, the cross-head pin passes through 



FITTING UP THE ENGINE, ETC. 127 

the cross-head, the connecting-rod end, and enters 
the centre of each of the " slippers." Place the 
connecting-rod on the crank-pin again, remove the 
upper guide-bars, take the pin out of the cross- 
head and the guides, place the free end of the 
connecting-rod in the slot of the cross-head, push 
the pin through the connecting-rod and cross- 
head, place the guide-blocks upon each end of 
this pin, and bolt down the top guides ; slip the 
eccentric-pulley with its strap and rod over the 
end of the crank-axle, key the fly-wheel upon 
its seat, on the crank-shaft near one end, and 
a small pulley upon the other ; screw a steam- 
pipe with a stop-valve, and an exhaust steam- 
pipe, into their respective openings, screw the four 
bolts for holding the slide-valve casing, into the 
cylinder face, and slip the valve-casing (having 
packed the stuffing-box and placed the valve on 
the spindle) over the bolts, after smearing the 
joint with red lead or inserting a piece of india- 
rubber, to make a steam-tight joint ; fasten this 
firmly on with two nuts, one at either corner ; 
keep the valve-cover off until the slide-valve is 



128 MODEL ENGINE CONSTRUCTION. 

properly adjusted. When measuring to get the 
proper length of the eccentric-rod, etc., always 
keep the slide-valve well pressed up against its 
seat by the finger, or by a temporary strip of 
brass inserted for this purpose. We must now set 
the slide-valve, and it is very important to adjust 
it correctly, or the engine will not work. By 
" setting " the slide-valve, we mean fixing the 
eccentric-pulley in a definite position in regard 
to the crank, that the relative positions of the 
slide-valve and piston may produce the result of 
permitting steam to enter and leave the cylinder 
at the proper times ; and in order to do this, the 
eccentric must be fixed ahead of the crank by a 
definite angle. We must first get the length of the 
eccentric-rod, which is done by placing the slide- 
valve in the middle of the cylinder face, so that 
the steam-ports are equally covered (the " lap " 
being equally divided). Now fix the eccentric 
temporarily, in any position on the crank-shaft, 
and turn the shaft round until the wide side of 
the eccentric is in its highest or lowest position, 
and measure from the centre of the pin in the 






FITTING UP THE ENGINE, ETC. 129 

valve-spindle cross-head to the bottom of the groove 
on the eccentric-pulley, which is the length of 
the rod, including the strap. The rod may be 
allowed a little longer than the actual measurement 
at first, as it can always be shortened; but its 
length can only be extended within very narrow 
limits. The free end of the rod must be drilled, 
where marked, to take the cross-head pin, and 
when attached, it should be adjusted to its true 
length, by screwing it in and out of the valve 
cross-head. Having fixed the eccentric-rod, turn 
the shaft round until the "throw" or wide part 
of the eccentric-pulley is in its furthest position 
from the cylinder, look how much the steam- 
port for the back of the cylinder is opened, then 
turn the shaft again, until the " throw " or wide 
side of the eccentric-pulley is in its nearest position 
towards the cylinder, and notice the amount of 
opening the front port of the cylinder has. If this 
port be opened wider than the back port was the 
rod is too long, and must be shortened half the 
amount that one port is opened wider than the 
other ; if the back port is too much opened, the 

K 



130 MODEL ENGINE CONSTRUCTION. 

rod requires lengthening half the difference, by 
unscrewing it further out of the eccentric-strap. 
When both ports are equally uncovered, the length 
of the eccentric-rod is correct. We must fix the 
eccentric-pulley upon the shaft so that steam shall 
be admitted to the cylinder at proper intervals 
during the piston stroke. To do this, bring the 
piston round to the back of the cylinder, the 
crank being nearest it on the inner dead centre, 
loosen the eccentric, and tyrrn it round upon the 
shaft until the back port is just open and no 
more, and might admit a very thin strip of paper ; 
then key the eccentric temporarily, and turn the 
shaft round till the crank is on the outer dead 
centre and the piston up at the front port : if the 
edge of the paper just enters the opening in this 
port, the valve is correctly set. This amount of 
opening before the piston commences its stroke 
is called " lead," and if it does not affect the ports 
equally, the length of the eccentric-rod must be 
re-adjusted. When the position for fixing the 
eccentric on the shaft has been found, mark it 
with a file ; this forms the key-seat on the shaft, 



FITTING UP THE ENGINE, ETC. 131 

and must correspond to the key-way in the eccentric- 
pulley; remove the key that was holding the 
eccentric temporarily to the shaft, push the pulley 
over to one side, and file a flat on the shaft. 
When this is done, put the eccentric back in 
position, drive the key in firmly, and the whole 
is complete. 

It will be apparent that the centre line of the 
eccentric must be in advance of the centre line of 
the crank by a little more than 90° ; this " little 
more" is called the "angle of advance." If there 
was neither lap nor lead, then the centre line of 
the eccentric would be at right angles to the centre 
line of the crank, or the eccentric be only 90° ahead 
of the crank. 

Having set the slide-valve, bolt the back cover on 
to the cylinder, making the joint tight with rubber 
or red lead, and do the same with the slide-valve 
cover. Mount the engine, and screw it firmly down 
upon a solid wooden block, of the same length and 
width as the bed-plate, having made holes in the 
top of the block, into which any nuts projecting 
underneath the bed-plate may enter; or instead of 



132 MODEL ENGINE CONSTRUCTION. 

this, the bed-plate may be fixed upon turned brass 
pillars, and these driven firmly into a wooden sole, 
which can be stained or varnished afterwards. 
After finishing an engine, it is a first-rate plan to 
connect it temporarily by means of coupling-screws 
and brass tubing to a horizontal boiler set over the 
kitchen fire (see page 36), and after steam is up, 
giving the engine a run of about an hour's duration. 
In this way, the engine gets into proper working 
order, and will run smoothly ever after. 



CHAPTEK V. 

EEVERSING-GEAR. 

Reversing-gear. By this is meant a contrivance 
fitted on the engine to enable it to run either back- 
wards or forwards. This is carried out in different 
ways : (1) By a loose eccentric on the crank-shaft 
(a) fixed by a set-screw, (b) working against a stop ; 
(2) by a link motion (a) having one eccentric fixed 
on the crank-shaffc, (b) having two fixed eccentrics 
on the crank-shaft. 

1. (a) A loose eccentric fixed by a set-screw. 
We must first set the eccentric on the crank-shaffc 
for running in one direction, according to the rules 
already given, mark the position of the set-screw 
on the axle, after the eccentric is properly set, and 
drill a hole in the axle at this point, into which 



134 MODEL ENGINE CONSTRUCTION. 

the set-screw enters for a short distance, and is 
tightened up. Then set the eccentric for running 
in the opposite direction, and drill a hole in the 
proper place on the axle for the set-screw as before. 
By simply changing the position of the eccentric, 
the engine will run in either direction. 

(h) The eccentric working against a stop. The 
eccentric, being loose on the crank-shaft, is driven 
backwards and forwards by a projecting feather, 
soldered or welded to the crank-shaft. A brass ring 
is fixed on the axle, on the opposite side of the 
eccentric, against which this latter bears, and is 
always kept up against the feather. Turning the 
fly-wheel in either direction causes the fixed stop 
or feather to come into firm contact with the 
forward or backward projection on the eccentric 
pulley; this projection or counter- weight should 
be firmly screwed or soldered to one side of the 
eccentric-pulley, and set in the proper position. 
With a little trouble the eccentric may be accu- 
rately fitted, by filing away part of the feather and 
counter-weight till properly set, and the counter- 
weight, being fixed to the eccentric-pulley, is carried 



BEVERSING-GEAB. 



135 



round by the feather either forwards or backwards, 
according to the direction in which the crank-shaft 
forces it. Both of these methods reverse the lead 



afcalher 




wnferrteiffiC 



Fig. 40. 



of the slide-valve as well as the engine, and act 
fairly well (see Figs. 40 and 41). 



Jl flUB 




ID 



Fig. 41. 



2. (a) Link motion with one fixed eccentric. This 
is an ordinary curved slot-link, pivoted (at its 
centre) to a support fixed on the bed-plate, having 



136 MODEL ENGINE CONSTRUCTION. 

the concave side turned towards the slide-valve ; this 
link remains fixed. The eccentric-pulley, being fixed 
on the crank-shaft (for the engine to run in one 
direction), has its forked rod pivoted to the top or 
bottom of this link, and a short connecting-rod 
passes from the end of the slide-valve spindle, which 
engages with the link by means pf a block called 
the "die-block," working in the slot of the link. 
By means of a lever moving it, this connecting-rod 
and block can be slid up and down the link, and 
though the eccentric-pulley is fixed to run in one 
direction only, by simply changing the position of 
the valve-spindle connecting-rod, the engine will run 
either way, but not so well as with the ordinary link 
motion (having two separate eccentrics), for it does 
not reverse the lead of the slide-valve in reversing 
the engine, and so gives an imperfect action to the 
valve when the engine is moving backwards. 

(b) The ordinary link motion (see Fig. 42), with 
two separate eccentrics, gives the best results of all, 
and we will describe it fully. The eccentric-pulleys 
are so placed on the crank-shaft, that when one is 
in the right position for forward motion, the other 



REVERSING-GEAR, 



137 



is in position for backward motion. The eccentrics 
are connected by separate straps and eccentric-rods 
to the ends of a link, whose concave side is turned 
towards the axle. In this link a die-block, connected 
to the slide-valve spindle, is fixed, and can be slid 
from end to end. By raising or lowering this link 




Fig. 42. 

(the die-block remaining fixed), so as to bring the 
valve-spindle in line with one or other eccentric- 
rod, the motion proper to that rod will be communi- 
cated to the slide-valve, and the engine will move 
backwards or forwards accordingly. The reversing- 
lever is held in position by a bolt working at its 
side, and is kept in the notches of a quadrant by a 
spring, and by means of a weigh-bar, shaft, and 



13S MODEL ENGINE CONSTRUCTION. 

levers moves the link up or down as required. If 
the link be placed so that the block is at the middle 
of the link, then the engine stops, since the valve is 
thrown into its mid-position. In real engines, the 
nearer the die-block is moved towards the centre of 
the link the shorter becomes the stroke of the slide- 
valve, and this produces an earlier cut-off of steam 
and increased grade of expansion, and advantage 
is taken of this fact to save steam and lessen the 
amount of coal consumed, by utilizing the full 
motion of the valve when starting the engine, and 
then soon notching up the reversing-lever for ex- 
pansive working. In models where the opening to 
lead is very small, we cannot take advantage of this 
plan — in fact it does not work well — but simply 
design the motion for full gears. This form of link 
motion reverses the lead of the slide-valve as well as 
the engine, and so causes the engine to run equally 
well in either direction. For further drawings, see 
Sheet No. 11, C, and Sheet No. 8, C. 



BEVEBSING-GJSAB. 139 



Details of Valve Gear. 

It is best to make two eccentric-pulleys, and key 
both separately to the crank-shaft in their respective 
positions, instead of having them cast together, and 
one key holding both. Two eccentric-straps and 
rods are required, each with a forked end, pivoted 
to the top and bottom of the slot-link respectively. 
The fork is a brass casting, slotted out, and screwed 
to the end of the rod ; one of the rods must be 
cranked, by reason of the relative positions of the 
eccentrics and the link, which cannot all be in 
the same plane. The slot-link requires great care 
in making, to get it accurate. It may be con- 
structed of sheet brass or iron plate. Take a 
triangular piece of metal, long enough to include 
the link, and the centre from which it is struck, 
punch and drill a hole through ; this represents the 
centre of the axle, and forms the starting-point for 
setting out the link. The curved centre line of 
the link is struck to a radius, which equals the 
distance from the centre of the axle to the centre 



140 



MODEL ENGINE CONSTRUCTION. 



of the valve-spindle cross-head pin, the slide-valve 
being set at "mid position/' and kept well pressed 
up against the port faces. With compasses, mark 
upon both sides of the metal the centre line of 
the link and all the other outlines correctly, and 
with a straight-edge draw the radii correctly (see 




Fig. 43. 

Fig. 43). Leave three snugs, two in front near the 
ends, and one projecting at one end for attaching 
the lifting-link to ; drill and file out the slot cor- 
rectly, but don't make it too long; mark and drill 
the hole for the eccentric-rod forks, through the 
snugs, in such a position that when the die-block is 
pushed to either end of this slot, a straight line, 
prolonged from the centre to the central hole in 



REVERSING-GEAR. 141 

the die-block, will pass through the centre of the 
holes for the eccentric-forks in each snug. These 
holes must be drilled in the line of curvature from 
the centre ; and the hole for the lifting-link pin, 
passing through the end snug, must be drilled in 
the centre line of curvature of the slot, at some 
little distance from* it (see Fig. 43), before cutting 




Fig. 44. 

the link to outline. From the centre, with a 
pair of compasses and a straight-edge test the 
accuracy of these different curvatures and radii 
upon both sides of the metal; if not correct, they 
must be filed away until they are. When this 
is done, proceed to cut the link to outline by 
drilling, cutting, and filing ; smooth it all over 



142 



MODEL ENGINE CONSTRUCTION 



with a file (see Fig. 44), then, if carefully made, 
the link will be found to act perfectly upon the 
valve. The eccentric-rods are attached to the 
link by bolts passing through the forks and snugs. 
The end of the slide-valve spindle must carry a 
brass fork, which embraces .the link but allows it to 
slide up and down upon its faces ; it also embraces 
the die-blocks. This block (see Fig. 43) is a piece 



® 



Fig. 45 



of brass accurately fitted, to slide along the slot- 
link, convex behind, concave in front ; the upper 
and under borders fit against the top and bottom 
edges of the slot when in contact with either end 
of the link. It is made slightly thicker than the 
link, but of an easy fit, so as to pass between the 
valve-spindle forks, and a transverse hole is drilled 
through its centre. Connect the link and valve- 



REVERSING-GEAB. 143 

spindle together, by placing the die-block in the 
slot of the link, and pass both between the eccentric- 
spindle forks, put a pin through both legs of the 
fork and die-block : the link oscillates upon this pin. 

Having now connected together the eccentrics 
and the slide-valve, let us turn to the lifting- 
links, weigh-bar, reversing-lever, etc., which provide 
for the reversing of the engine. 

The lifting-links (see Fig. 45) are straight or 
curved, made of soft iron filed flat on opposite 
sides. In large engines there are two, one is placed 
on each side of the slot-link ; in models Ave may 
use one only. One end of this link is pivoted to 
the top, the bottom, or the centre of the slot-link, 
the other end to the weigh-bar lever. The end 
that engages the link, should have a projecting 
boss upon the inside, to keep it at a fixed distance 
from the slot-link, so as not to interfere or strike 
against the slide-valve fork and eccentric-forks 
Avhen lifting up and down. The same thing may 
be accomplished by placing washers between them. 

The weigh-bar is a piece of iron wire, fixed in 
bearings, placed at a suitable distance from the 



144 MODEL ENGINE CONSTRUCTION. 

slot-link, so as to allow of the latter moving up 
and down freely. It has firmly fixed to it a lever 
which at one end pivots to the lifting-link, and at 
its other end is prolonged behind the weigh-bar for 
a certain distance, and carries a balance weight — 
consisting of a piece of brass, cored out for the lever, 
which passes through it — which is fixed in position 
by a set-screw. There is another short lever keyed 
to this weigh-bar, which by its free end is pivoted to 
a rod, which again is pivoted to the reversing-lever 
working in a quadrant. This quadrant is a small 
casting, having feet or lugs, by which it is bolted 
to the bed-plate, or the foot-plate of a locomotive. 
The quadrant must be correctly curved at the top to 
suit the locking-bar, and notches cut in it to corre- 
spond with full-forward, backward, and mid-gear. 
(The positions for these notches should be found 
out by trial with steam afterwards.) 

The reversing-lever is an iron rod forged or filed 
out of iron wire, with a turned handle on the top. 
It is pivoted to the foot of the quadrant, and a rod 
is pivoted to the lever (see drawing) a short way 
under the " notch-plate," which by its other end 



BEVEBSING-GEAB. 145 

engages with the short lever on the weigh-bar. 




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A small spring attached to the handle of the 



146 MODEL ENGINE CONSTRUCTION. 

reversing-lever, causes the locking-bar to be thrust 
down into the notches. Pressing a small lever 
towards the handle compresses the spring, and lifts 
the locking-bar out of its notch. At the lower end 
the bar, which is pivoted to the small lever, is 
held close to the reversing-lever by a ring that 
surrounds both of them. Good fitting of all pins 
and joints is necessary to ensure accuracy, for if 
the parts be fitted up too tight, or too slack, the 
gear will work badly and be a failure. 

In a locomotive there is precisely the same 
arrangement of the gearing, but as there are two 
cylinders there must consequently be two slot-links, 
four lifting-links (assuming there is one on each 
side of the slot-link), four eccentrics, two counter- 
balanced levers attaching the lifting-links to the 
weigh-bar, and one short lever again connecting the 
weigh-bar, by means of a rod pivoted to it, with the 
reversing-lever in the quadrant on the foot-plate. 

An expansion-valve (see Fig. 46) is a valve fitted 
steam-tight to, and working on, the back of an 
ordinary slide-valve. It is used in engines for obtain- 
ing high grades of expansion of steam, which the 



REVERSING-GEAR. 147 

ordinary slide-valve is not well fitted to give, as 
sufficient opening to steam cannot be obtained with 
it for an earlier cut-off than, say, half-stroke, with- 
out unduly increasing the travel and the lead. In 
marine engines the expansion-valve is worked by 
a separate eccentric fixed upon the crank-shaft, the 
eccentric-rod of which connects to a straight link 
moved by a horizontal screw, and a pair of bevel- 
pinions, so that different grades of travel — and con- 
sequently of expansion — may be obtained. The 
nearer the eccentric-rod is placed in line with the 
expansion-valve spindle, the greater the travel and 
the later the cut-off. But the plan we are going 
to adopt here is to connect the expansion-valve 
spindle direct with a Hartnell's governor, as is done 
upon large engines by Messrs. Marshall and Co. 
of Gainsborough, and probably by other makers as 
well. A model expansion-valve, though not re- 
quired to regulate the steam, if well fitted has a 
fine appearance, and makes the engine look more 
finished. 

The slide-valve (see Fig. 46) somewhat resembles 
the ordinary slide-valve, by being box-shaped and 



148 MODEL ENGINE CONSTRUCTION. 

attached to the spindle in the same way, but is 
much longer, and during its travel it never leaves 
the ports uncovered at the ends, for steam to pass 
into them round its edges. It is so constructed 
that all the steam passing through the cylinder- 
ports must first pass through the valve itself, and 
it contains for this purpose a port near either end. 
Make a brass slide-valve as before, and, in order to 
keep clear of the spindle, drill near each end two 
holes, one on each side of the spindle in a slanting 
direction, so that they join underneath the spindle, 
and come out on the face as one hole, near each 
end. These ports are for the admission of steam 
to the cylinder ; the valve exhausts in the same 
way as before. This valve-spindle passes through 
a stuffing-box, and connects, by the eccentric-rod, 
with an eccentric-pulley keyed to the crank-shaft, 
and set according to the rules already given, so 
as to admit steam to the cylinder when required. 
This valve regulates the point of admission, release, 
and compression, but not the cut-off; this last is 
regulated by the small valve that works on the 
back or top of the slide-valve, and which is directly 



REVERSING-GEAR. 149 

connected with the governor. It consists of a single 
brass plate with two faces (the best arrangement in 
a model), or two plates working steam-tight on the 
back of the slide-valve. These plates are kept at 
a fixed distance apart by collars fixed on a spindle, 
which passes through a second stuffing-box in the 
valve-casing. The action of these plates is to cut 
off the steam at any desired part of the piston's 
stroke, and prevent it from passing through the 
slide-valve and cylinder-ports into the cylinder. 
The free end of the expansion-valve spindle has 
a die-block, which engages with a curved link 
attached to the governor. 

A Hartnell's governor has some resemblance to 
that on page 119. It is driven by a pulley keyed 
on the crank-shaft, and this pulley is connected 
by a belt or cord with another pulley keyed on 
a vertical spindle, which by its other end supports 
the balls, which are fixed to bell-crank levers ; these 
balls revolve with the vertical spindle. The inner 
ends of the two bell-crank levers bear on a spiral 
spring contained in or above the metal sleeve. On 
the lower end of this sleeve is fixed a double collar, 



150 MODEL ENGINE CONSTRUCTION. 

engaged by a forked lever, suspended from which is 
a drag-link, the lower end of which is attached to 
the end of the expansion-valve rod ; the end of this 
rod ensues a die-block, which can be drawn from 
one end to the other of the link-slot, which is curved 
towards it, and to the centre of this link is attached 
the expansion eccentric-rod, the other end of which 
is attached to an eccentric-pulley fixed on the 
crank-shaft. 

Action. — When the speed of the engine exceeds 
the normal, the balls fly outward and compress the 
spiral spring, lifting the brass sleeve, the drag-link, 
and the expansion valve-rod with die-block, towards 
the upper end of the curved ■ link, thus diminishing 
the travel of the expansion-valve, and cutting off 
steam much earlier, which reduces the speed to the 
normal. When the speed falls below the normal 
the opposite takes place, for the spiral spring over- 
comes the compressive pressure of the bell-crank 
levers and presses down the sleeve, the drag-link, 
and the expansion valve-rod with die-block towards 
the lower end of the curved link, thus increasing the 
travel of the valve, and causing a later cut-off, which 



REVERSINa-GEAB. 151 

tends to increase the speed again. This governor 
is more accurate in its action than the throttling 
one, and does not seem very difficult to construct, 
though we think the amateur will require to make 
patterns for castings to fit up large-sized models of 
this piece of mechanism, which any one who could 
fit up the throttling-governor and link-motion would 
be able to do. 

A small-sized governor for a |" bore cylinder 
engine might be constructed without castings. Make 
the vertical support by sawing and filing a brass 
block to shape shown, turn the balls and arms out 
of brass rod, make a wire spindle, and procure 
small bevel pinions and a spiral spring from any 
watchmaker. The links can be cut out of strong 
sheet brass, the curve of the slot-link being struck 
at a radius from the centre of the slide-valve when 
set at " mid-position " ; the various rods and links* 
can be pivoted on each other with fine copper 
rivets, and with small bolts and nuts. When 
finished, the governor is bolted by the sole to the 
bed-plate of the engine, and the expansion-valve 
and eccentric-rods can be made of any desired 



152 MODEL ENGINE CONSTRUCTION. 

length, according to the distance between the 
cylinder and the crank-shaft. 

Joy's valve-gear (see Fig. 47). This form of gear- 
ing does away with eccentrics and the ordinary link 
motion. It is applied both to marine engines and 
locomotives, and a working model of it would not 
be very difficult to construct. The motion of the 
slide-valve is carried out and the reversing of the 
engine effected by a number of links and connections 
between the connecting-rod and the valve-spindle. 
At a joint C, on the connecting-rod CR, is attached 
a double link CL; about one-third the distance of 
this double link is attached a pair of double links 
VL, their upper ends first being attached to a 
sliding-block SB, which works in a curved slot-link 
FF, and then are pivoted to the valve-spindle con- 
necting-rod VSL, which connects with the valve- 
^pindle and the slide-valve. The lower end of the 
double links CL is connected to a radial rod AL, 
which is pivoted to a fulcrum B, bracketed to the 
frames. The slot-link FF (the radius of which is 
struck from the centre of the slide-valve when 
placed in "mid-position") is free to move to the 



REVERSING-GEAR. 



153 



ria\ht or to the left, in bearings carried on the engine 
frame. We see that while the point C of the con- 




necting-rod (to which the connecting-link is attached) 
describes an oval, the point A of the latter describes 



154 MODEL ENGINE CONSTRUCTION. 

a flattened ellipse, thereby imparting an equal motion 
to the point X. The motion is reversed by the lever 
R, which is fixed to one end of the quadrant-shaft 
Q ; the direction of the engine and the travel of the 
valve is regulated by the position in which the 
quadrant-shaft is placed. 

Fig. 48 is a diagram showing the action and 
expansive working of steam in the cylinder at various 
parts of the stroke, and the relative positions of the 
piston, crank, and slide-valve. By kind permission 
of the publishers, Messrs. Whittaker, this plate has 
been reproduced from Mr. Cooke's book on British 
Locomotives, to which work we refer our readers for 
a description of this drawing. 



R^ 



i 




2ZZZZZZZZZZZZZZZZZZ 



• 2ZZZZZZZZZL 









zzzzzzzzzzzzzzzzzza zm 





FigT 

Stroke Commences 

/^ Cenire line of 1 — __ 

Connecting rod/ 



Wf//WMMiM r \ Tiff 2 

Steam pert ihll open> 




/ 



/ 



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O 



Fig. 48.— Action of Steam in Cylinder, etc. 



PART II. 

DIFFERENT TYPES OF ENGINES: 
STATIONARY, LOCOMOTIVE, MARINE. 



CHAPTER VI. 

BEAM, HORIZONTAL, AND VERTICAL ENGINES. - 

Having described trie engine in detail, how to 
make and fit together the different parts, we will 
now describe and illustrate a few different types of 
engines; and any one who can make a horizontal 
engine, will find little difficulty in constructing any 
of the forms we take up, as with slight variation 
they are all fitted up in a similar way. 

We give working drawings of a high-pressure 
beam engine — condensing apparatus and pumps 
omitted — (see Fig. 49 and Sheet No. 3). This is 
undoubtedly the oldest style of engine in existence, 
Newcomen having constructed an atmospheric beam 
engine for pumping purposes as early as the year 
1712. This engine, in the hands of Watt, under- 
went great improvements, and was made double- 



158 



MODEL ENGINE CONSTRUCTION. 



acting by him in 1784 : this style is similar to 
those constructed at the present day. 

By reference to the drawings it will be seen that 
the cylinder is bolted to the bed-plate so as to 




Fig. 49. 



stand vertically, and the cross-head is attached to 
one end of a large beam, which oscillates by its 
centre in bearings fixed on supporting columns ; the 
reciprocating movement of the piston is communi- 
cated to the beam, and by it is transmitted through 



BEAM ENGINE. 



159 



the connecting-rod at its opposite end to the crank- 
shaft and fly-wheel. The end of the beam moves 
in the arc of a circle, while the piston's motion is 
truly vertical ; and to get over this difficulty use is 
made of the celebrated invention of James Watt, 




Fig. 50.— The " Parallel Motion." 



which is known as the " parallel motion " (see 
Fig. 50). 

From what we have just said, it will be seen that 
it is impossible to join the cross-head and the beam 
directly together, so they are connected by means 
of a short rod AB, which with the other two rods 
DA, DC, together with part of the beam CB, form 
a jointed parallelogram, the angles of which vary 



160 MODEL ENGINE CONSTRUCTION. 

according to the position of the beam ; the angle D 
is connected by a joint with the end of a small rod 
DO, movable on a pivot at 0. Effect. — If the beam 
be horizontal, and the end B rises, A will pass to 
the left by the beam's action, and to the right by 
the action of the small rod DO, which, by checking 
the movement of the piston-rod to either side, is 
called the bridle-rod. These two opposite move- 
ments balance each other, and so the piston-rod 
keeps in a vertical straight line, and other than 
this, no guide-bars are required. The slide-valve 
and spindle (see Sheet No. 3) are vertical; rods A 
pass vertically on each side, and by means of bell- 
cranks B connect with the eccentric-rod, which 
works at right angles to the slide-valve. A throt- 
tlinof-o-overnor is used to regulate the admission of 
steam to the cylinder, and this is driven by a pulley 
on the driving-axle. 

Castings for making a beam engine may be pur- 
chased from the model-maker's, the names and 
addresses of a number of whom will be found on 
page 309. Either a vertical or a locomotive boiler 
can be used to drive this engine. 



HORIZONTAL ENGINE. 161 

The horizontal engine (see Sheet No. 4). After 
what has been said, we will not dwell long upon 
this type of engine. The working drawings give an 
elevation, a plan, and an end view of a horizontal 
centre-crank engine. The cylinder is ■§■" bore, |" 
stroke, fly-wheel 3 J" diameter. The engine is fitted 
with a throttling-governor, double iron motion bars, 
grease and blow-off cock, and oil-cups. The exhaust- 
pipe comes out under the bed-plate, and this latter 
is slotted out underneath the axle to allow of the 
eccentric-pulley and crank passing round when re- 
volving ; the bed-plate is supported by six turned 
pillars erected on a wooden sole. A drawing of the 
bearings is given full size. The centre crank-axle 
can be a built-up one, screwed and soldered together 
with brass crank- webs (see page 104). 

Sheet No. 5 gives an engine of much simpler con- 
struction than the above. The cylinder rests upon 
two feet, which raise it so high, that the connecting- 
rod when revolving keeps clear of the bed-plate, 
and no slot is required in the latter. Two circular 
guide-bars of iron wire are screwed, one at the top 
and the other at the bottom, to the front cover of 

M 



162 MODEL ENGINE CONSTEUCTION. 

the cylinder, their free ends being soldered into a 
brass ring which is supported upon the bed-plate. 
The cross-head carries two guide-bars, which are 
slotted out, to be an easy fit between the bars 
when working; the connecting-rod is forked at the 
cross-head end; the crank is placed at one end of 
the shaft; the eccentric-strap is made of sheet 
brass, and contains a loop through which the rod 
is screwed (see page 116) ; the exhaust-pipe passes 
vertically upwards, and the steam-pipe carries a 
coupling-screw for attaching to a boiler. 

A horizontal engine is the easiest of all model 
engines to fit up, and when made has a fine 
appearance. Castings for making it can be had 
from any of the model-makers, and vary in price 
from a set with a J" bore cylinder at Is. 6d., up to a 
small-power engine (2" bore cylinder) with castings, 
including governor, pump, and forgings, at about £2. 
Larger sizes can also be had. 

The castings included in a set are a cylinder, 
two cylinder covers, piston, two stuffing-boxes and 
glands, guides, slide-valve case, two bearings, eccen- 
tric-pulley, eccentric-strap and rod, connecting-rod, 






VERTICAL ENGINE. 163 

cross-head, fly-wheel, pulley, and slide-valve. The 
larger sizes have in addition governor and force- 
pump castings ; the bed-plate, pillars to support 
it, and crank-shaft forgings are extras, and not 
generally included in a set. 

The vertical engine (see Sheet No. 6) is similar 
in form to the last, but is arranged vertically instead 
of horizontally, and consequently occupies less floor 
space. We shall mention the fitting up of the 
parts only that vary, in this engine, from the 
analogous parts in the horizontal engine. In the 
drawings, there is a front and side elevation shown. 
File the bed-plate quite flat, drill holes for the 
cylinder bolts to pass through, corresponding with 
the holes in the covers and cylinder flanges, bolt 
down the cylinder with the cover to the plate, or 
omit the cover and let the bed-plate form the 
bottom cover for the cylinder. 

Be careful that a line passing through the centre 
of each guide-bar and the centre of the piston-rod, 
is at right angles with the centre line of the crank- 
shaft. File the standards smooth and level, and 
finish as described on page 100 ; drill the feet of the 



164 MODEL ENGINE CONSTRUCTION. 

standards, and make corresponding holes in the 
bed-plate for the bolts to hold them down by. The 
iron wire guide-bars are screwed into the front cover 
of the cylinder, and have the piston-rod exactly in 
line between them when drawn out ; the free ends 
of the bars are screwed into two brass supports, the 
ends of which pass through the standards, and are 
held in position by nuts. The cross-head has the 
slippers cast upon it, one on each side ; these must 
be filed over, so that when the cross-head is screwed 
on to the piston-rod, the slippers are a sliding 
fit between the guide-bars. The connecting-rod is 
forked, and embraces the cross-head, a pin passing 
through both ; the other end is fitted with brasses 
as described on page 97, and is then put over the 
crank-pin; this pin is screwed into the crank-web, 
and has a small washer on each side to keep the 
connecting-rod " big end " from rubbing on the 
crank-webs. For the construction of the crank-shaft, 
see page 103. When the engine is put together, 
the bearings must be level with each other, and the 
shaft run quite easily. Fit up the eccentric, fly- 
wheel, and pulley, key these in position on the 



VERTICAL ENGINE. 165 

crank-axle, pack the stuffing-boxes, and bolt the 
bed-plate down to a block of wood, and the engine 
is ready for steam. 

An inverted vertical engine is shown upon Sheet 
No. 7, which contains the working drawings. In 
this type, the cylinder is raised above the crank- 
shaft, and is bolted to the guide-blocks. The bed- 
plate is a casting, either resting on feet or bolted 
to a block of wood. It is slotted out, to allow 
the crank with connecting-rod end to pass through, 
when revolving. The bearings are of brass, bolted 
by feet to the bed-plate. The guide-blocks, the 
front cover of cylinder, and stuffing-box are in one 
casting, and these are bolted to the bed-plate. In 
fitting up, find the centre of the front cover, punch 
and drill a hole vertically through for the piston-rod, 
coming out in the centre of the slide-blocks ; turn 
this casting upside down, and widen the hole from 
the stuffing-box end for about three-quarters of its 
depth, fit on a gland (see page 85), screw the piston- 
rod into the cross-head, after the guide surfaces have 
been filed flat, file the inside of the guide-blocks 
smooth, insert the cross-head between the guides, so 



166 MODEL ENGINE CONSTRUCTION. 

that the piston-rod passes up through the stuffing- 
box, the gland, and the front cover. After pack- 
ing the piston stuffing-box, screw the piston and 
the follower (if there be one) on to the piston-rod 
firmly, then take the cylinder and slip it over the 
piston ; see that it rests on the front cover equally 
all round, and the piston works up and down easily 
(this part of the fitting is rather difficult, unless the 
cover has been faced on the lathe). When this end 
is attained, and the cylinder is correctly set, mark 
and drill bolt-holes in the cover, to correspond with 
those already made in the cylinder flange. If the 
bolts be screwed into the cylinder flange, the holes 
in the cover must be widened with a rimer so that 
the cylinder will pass over the piston, and all the 
bolts (in its flange) pass easily into their respective 
holes. Next tighten up the cover with nuts. If 
the bolts be screwed into the cover, then the holes 
in the cylinder flange must be widened, and nuts 
put on upon the top of the flange — either plan will 
hold the cylinder. — After doing this, there will be 
no difficulty experienced in finishing the engine. 
The castings for a vertical engine consist of the 



VERTICAL ENGINE. 167 

following parts : a cylinder, two covers, slide-valve 
and case, piston, two glands, cross-head, connecting- 
rod, guide, two standards, eccentric and strap, crank- 
shaft, fly-wheel and pulley ; and these vary in price 
from 3s. 6d. up to £1, according to the size chosen ; 
the bed-plate, columns (if any), piston, and slide- 
valve rods can be had at an extra cost. 



CHAPTER VII. 

TRACTION, PORTABLE, AND SEMI-PORTABLE 
ENGINES. 

A traction engine. A perspective view of this 
engine is given in Fig. 51, as well as working draw- 
ings with dimensions (see Sheet No. 8, A, B, and C). 
The boiler is made in the same way as the loco- 
motive boiler described on page 37. It is made 
of sheet copper, the barrel and outer fire-box of 
No. 24 sheet copper, and the internal fire-box, fire- 
tube, and tube-plate of No. 21 sheet copper, all the 
joints in it being brazed. The smoke-box is made 
of tin, circular in shape; it surrounds the front of 
the boiler for about T V', and is made a very tight 
fit round the barrel ; it may be attached by solder. 
The funnel is -J " wide, to maintain a good draught 
of air through the fire-box. Eight wicks burn in the 



TRACTION ENGINE. 



169 



fire-box, four in a row, and a space of nearly half- 
an-inch is left on both sides and in front, between 
the sides of the outer fire-box (below the water- 
line) and those of the lamp for admission of air, 




Fig. 51. — Perspective view of Traction Engine. 



and this, coupled with the large fire-tube and wide 
funnel, maintains a good draught when the engine 
is at work. The fire-box is open at the bottom, 
except the space occupied by the lamp. On the 



170 MODEL ENGINE CONSTRUCTION. 

boiler near the funnel, upon the left side, there 
is a water-plug inserted, a lever safety-valve, -§" 
diameter, is fixed in front of the cylinder, with a 
spring-balance pivoted to a bracket soldered on the 
boiler; the valve can be tightened with a nut 
in the usual way. The cylinder, slide-valves, and 
link-motion (see working drawings) must be made 
according to the directions for making these articles 
under their respective headings. 

The cylinder is f " bore, f " stroke ; it is fixed by 
a coupling-screw to the steam-pipe, and rests on the 
top of the boiler near the funnel. There is a top 
and bottom circular guide-bar, both of which are 
soldered at their free ends into a ring made of sheet 
brass, and which rests on a fork when in position. 
The piston is \" broad, having a -|" groove for 
packing, with a T V' collar on each side. The steam- 
pipe, about -§•" diameter, comes out upon one side 
of the boiler, where, after having a cock screwed on, 
it joins, by means of a coupling-screw, with the 
steam-pipe leading to the cylinder; the other end 
of the steam-pipe is bent up inside the boiler to 
take steam as dry as possible, and prevent priming. 



TRACTION ENGINE. 171 

A piece of sheet brass or tin, of the same length 
as the cylinder, may be moulded round the latter 
on the side opposite to the valve-spindle, then 
curved downwards and be bent so as to rest by 
a small collar upon the boiler, to which, instead 
of by studs, it might be attached by a little solder. 
This makes the cylinder look as if it was encased 
in a jacket, at least upon one side, and gives it addi- 
tional support to that derived from the steam-pipe, 
to which it is attached by means of a coupling-screw 
or union, so that by loosening the solder and the 
coupling-screw, after disconnecting the connecting- 
rod and eccentric-rods from the link, and the latter 
from the lifting-links, the cylinder can be raised 
up, the blast-pipe brought out of the funnel, and 
then easily removed for purposes of packing the 
glands, etc. A -§■" cock screwed into the steam-pipe 
below the coupling-screw controls the steam to the 
cylinder; a wire running along the side of the boiler, 
terminating in a crank handle (the regulator), opens 
and shuts this cock. 

The end of the valve-spindle rod is forked, and 
embraces the slot-link, which is cut out of a piece of 



172 MODEL ENGINE CONSTRUCTION. 

sheet brass. The slot is struck to the correct curve, 
then drilled and filed to outline (see page 139). 
A snug is left at one end for pivoting to the lifting- 
links ; these lifting-links, instead of being pivoted 
to one end of the slot-link, could be pivoted by a 
short arm to a central snug formed between the 
eccentric-rod snugs, and in this way the link would 
be raised and lowered much more easily than when 
pivoted by one end, and the engine would tend to 
work with less friction. The use of the short arms, 
one on each side, is to keep the lifting-links in a 
lateral line with the slot, and raise the link at the 
same time from the centre. Both arms must be 
bent outwards, so as to keep the lifting-links clear 
of the ends of the valve-spindle and of the eccentric- 
rods when raised and lowered. The lifting-links are 
made of sheet-brass strips, pivoted by a fork at the 
lower end to the weigh-bar, which revolves in bear- 
ings on the boiler; a small crank or slotted lever 
with a pivot is fixed at one end of the weigh-bar, 
this raises and lowers the link, and is worked by a 
sheet-brass rod, -f$" broad, pivoted to the reversing- 
lever on the foot-plate, which works in a racket. The 



TRACTION ENGINE. 173 

eccentric-pulleys are turned out of solid brass rod, 
bored and soldered on to the crank-shaft ; they are 
|" diameter over all, including collars ; one is set 
for forward and the other for backward motion, but 
neither of them have scarcely any lead. The straps 
are of sheet brass, and the rods of brass wire (see 
page 116). The brass ends of the rods that em- 
brace the links are forked, and are screwed to the 
ends of the (wire) rods. This forked end is made 
out of a piece of brass, with a saw-cut into which the 
slot of the narrow link passes. Both the fork and 
the link is drilled, and a small pin passed through 
to form a joint, and this is fixed to the outside of 
the fork by a bit of solder : plenty of free play 
must be allowed to the link on the pin. The other 
eccentric-rod is attached in the same way to the 
other snug on the link. In such a small engine, 
very great care must be taken, when adjusting the 
eccentric-rods, to make certain that they are both 
of the same length, as well as the proper length, for 
a very slight difference in their respective lengths 
will prevent the engine from running well, or even at 
all in one direction, while it will go whirring round 



174 MODEL ENGINE CONSTRUCTION. 

in the other, and the cause of this seems rather 
puzzling to discover at first. In all cases, when it 
can be done, the slide-valve should be properly set, 
with the valve-cover removed, the cylinder being 
kept firmly fixed in position; press the slide-valve 
up against the steam-chest, following the rules given 
in Chap. IV. Do this with the forward eccentric-rod, 
setting it properly ; then reverse the engine, turn 
the fly-wheel by hand in the opposite direction, and 
do the same with the backward eccentric. When 
it is impossible to remove the valve-cover after the 
cylinder is fixed in position, as in the case of loco- 
motives, the valve-spindle must, before adjusting the 
eccentric-rods, have filed very lightly upon it marks 
showing its relation to the ends of the stufnng-box, 
or some fixed mark, when one port is full open, and 
when the other port is full open, and these file- 
marks are the guides when adjusting the lengths 
of the eccentric-rods. A small plug-hole leads into 
the valve-case, which is closed with a screw-plug; 
this serves for oiling purposes and for blowing out 
water from the cylinder before starting, or if the 
boiler should prime, as it may do if filled too full of 



TRACTION ENGINE. 175 

water. The links are pivoted together by very fine 
rivets, made with a file out of thin copper wire ; a 
head is left at one end, and the other end is put 
through the holes in the links, cut short, and riveted 
with a light hammer against the vice or an iron 
block ; the superfluous part of the rivet-head can be 
filed off to look neat. If hammered tight, the rivet 
makes the parts quite a fixture (there is no joint) ; 
if hammered only so tight as to leave a little play, 
the parts joined form good workable joints for the 
link motion. If one lifting-link only is fixed on, 
this must pivot freely on the end of the short arm 
by which it is attached to the slot-link, while the 
other end of this arm is riveted immovably to the 
central snug of the slot-link. If there are two 
lifting-links, these pivot on a wire that passes 
through the upper end of the slot-link, and are 
retained on the wire by outside nuts. 

The fly-wheel is 3" diameter, of brass, screwed 
on to the built-up crank-shaft (see page 105). The 
axle revolves in solid bearings, fixed in holes slotted 
out in the side-plates. The axle is small, so instead 
of turning it down narrower at the journals, solder 



176 MODEL ENGINE CONSTRUCTION. 

on two brass rings, in such a position that one lies 
inside the one bearing, and the other inside the 
other bearing ; these prevent the axle from shifting. 
The rings are made out of sheet brass, and slipped 
over the ends of the axle. Each bearing is nearly 
yY" thick (the thinner they are the more easily does 
the engine work), and has a hole drilled through 
it for the axle to pass, with a small vertical hole 
leading to the journal for oil. 

The road-wheels. The hind ones are 4|" dia- 
meter, and 1" broad; the rim of each wheel is 
made out of sheet brass, 13^" X 1", bent circular 
and soldered inside, at the overlap. Two collars cut 
out of tin, about T y broad, are soldered all round 
the rim ; one collar goes inside, near the outer edge 
of the rim, and the other collar is placed at an 
equal distance from the inner edge of the rim, and 
these are for attaching the spokes to. To make a 
collar, take a piece of sheet tin. From the centre 
with compasses describe a circle, say 4" diameter, 
then make a narrower circle inside, 3f" diameter; 
cut the tin to the outline of the outer circle, then 
cut to the outline of the inner circle; the narrow 



TR ACTION ENGINE. 177 

strip between the circles must be hammered and 
bent straight : it is best to halve it. Place this 
collar inside the rim (as mentioned above), and 
solder all round ; if the ends overlap, they must be 
soldered together. Four collars are required, two 
for each wheel. A number of small narrow strips 
of tin can be soldered in a slanting direction at 
intervals around the rim of the wheels, to repre- 
sent the cross steel plates in a real traction engine. 
The nave of the wheel is composed of a central 
boss, 1" long, made of the finest brass tubing, and 
two central discs, one outside and the other inside, 
to which the spokes are attached ; the wire axle 
passes through the brass tube in both wheels. 
Upon one of the wheels the brass tube will be 
about 1-J-" long, and is left so as to project on one 
side of the wheel, and a tooth-wheel is firmly sol- 
dered to this projecting boss, so that it may gear 
with the other tooth-wheels ; a pulley is soldered 
to the inner edge of the projecting boss of the 
opposite wheel for the brake arrangement, the wire 
axle passing through both pulley and tooth-wheel 
on opposite sides. Both wheels are loose on their 

N 



178 MODEL ENGINE CONSTRUCTION. 

axles, and are kept in position from coming off by 
means of small nuts screwed on the ends of the 
axles. 

To make the central disc and the spokes, take 
a piece of tin, describe a circle 6" diameter, 
then a smaller one from the same centre, f" dia- 
meter, mark out between the circles eight radii, 
or spokes, each -§-" wide, cut the tin circular to 
outline, then cut out the pieces of tin between 
each spoke up to the f" circle. Now we have a 
central disc, and eight spokes radiating from it ; 
four of these central discs and spokes are required, 
two for each wheel. Each disc is bored in the 
centre, and soldered at one edge on to the central 
boss ; a space of about -|" is left between them, and 
they are fixed so that the spokes on the one side 
alternate with those on the other. It will be seen 
that in each wheel the spokes are sixteen in 
number, and that all the outside spokes are bent 
inwards, then cut short, and soldered to the collar 
upon the inside of the wheel; those again on the 
inside of the wheel are bent in the same way, cut 
short, and soldered to the collar on the outside of 



TRACTION ENGINE. 179 

the wheel ; thus the spokes or arms both alternate, 
and cross each other at the same time, as in a real 
traction-engine wheel, except that instead of rivets 
to fasten them we use solder. After fixing a tooth- 
wheel to the projecting boss on the inside of one 
wheel, and a small pulley to the projecting boss 
on the inside of the other wheel, both wheels are 
complete, and may be laid aside till the rest of the 
engine is completed. Washers, which can be made 
of pieces of brass tubing, may be slipped over the 
wire axles, between the wheels and sides of the 
fire-box, to keep the wheels at the proper distance 
from the fire-box on the inside, and nuts can be 
screwed on to the ends of the axles on the outside. 
The wheels must have plenty of play, and be quite 
loo.se upon their axles. 

The axle is made of iron wire ; this passes 
through the central boss of both wheels, and is 
firmly screwed into a brass block soldered on each 
side of the outer fire-box. The road-wheels require 
care in constructing, and are troublesome to make, 
to get them truly circular, and the crossed arms 
properly attached to the outside and inside collars, 



180 MODEL ENGINE CONSTRUCTION. 

but when finished they resemble ordinary traction- 
engine wheels. 

The front wheels are similar to the last, but 
much smaller, 1|" diameter, -§■" broad, each with 
ten spokes. There is only one collar inside, soldered 
to the middle of the rim. The arms alternate and 
cross each other, as in the hind wheels. The wheels 
are fixed loosely on their axles, and are kept in 
position by the sides of the frame on the inside, and 
by nuts on the outside : they are provided with 
radial gear. The frame is made of No. 20 sheet 
brass, with an angle-plate projecting behind and at 
both sides, through which the axle passes. A raised 
disc is soldered on to the top of the frame, midway 
between the wheels, and this disc is pivoted to and 
rests upon another disc, riveted by means of two 
projecting flanges to the bottom of the smoke-box. 
The direction of the wheels is controlled by two 
small chains, attached to eye-bolts, which are fixed 
near each end of the back plate of the radial-gear 
frame. These chains pass one on each side over, 
and are fixed by small bolts to a brass roller — made 
of wire — revolving in two bearings, soldered one at 



TRACTION ENGINE. 181 

each side of the front of the fire-box; one chain 
goes over, the other under the roller, and are wound 
once or twice round it, before being fixed by their 
ends to the bolts which pass' diametrically through 
the roller. On one side the roller has keyed or 
soldered to it a bevelled tooth- wheel, which gears 
with another spur-wheel, fixed to a shaft supported 
in bearings above and below ; this shaft passes along 
to the foot-plate, and ends in a hand-steering wheel 
placed at the driver's left hand. Turning this wheel 
with your hand, when the engine is running in 
either direction, winds one chain round the roller, 
tightening it, and unwinds the other chain at the 
same time, and so causes the radial frame to revolve 
on the central pivot — which consists of a bolt passing 
through the centre of each disc. This makes the 
engine run forward in a straight line when both 
chains are kept equally tight on the roller, or go 
to either side, according to whichever chain is the 
tightest. The tie-rod is a brass rod running in the 
median line, from the front of the fire-box to the centre 
of the back angle-plate of the radial frame. This is 
quite unnecessary, but renders the engine complete. 



182 MODEL ENGINE CONSTRUCTION. 

Tooth-wheel gearing. It is unnecessary to state 
the sizes of the wheels and pinions, as that can 
be ascertained by referring to the drawings, and also 
to mention the nunrber of teeth in the various 
pinions and wheels, for so long as the wheels and 
pinions do not lock when revolving, the gearing will 
work perfectly : it only connects with one road- 
wheel. This wheel carries a tooth-wheel fixed on 
the inside projecting boss, and connects by means 
of the other tooth-wheel and pinions with the 
fly-wheel shaft. When it is desired to make the 
engine travel, this object is attained by the upper 
pinion : this pinion, by means of a lever pivoted 
to a bracket projecting out from the side frame, 
and working in a curved fork at its other end, 
can be thrown into gear with the road-wheel by 
slipping the pinion over the end of the crank-shaft, 
and letting the slot in the boss come in contact 
with a feather soldered on to the end of the crank- 
shaft (see Sheet No. 8). This lever carries a ring 
on its under surface, pivoted to it, and through this 
ring the outside projecting boss of the pinion passes, 
and revolves inside. This is retained in position by 



TRACTION ENGINE. 183 

a collar soldered on to the end of the boss, and when 
fixed, a pin passes through the fork and the lever to 
steady it. When the pinion is on the crank-axle the 
feather enters the slot in the boss, and the pinion 
revolves with the axle, and this carries all the 
other wheels and pinions, as well as the road-wheel, 
round with it. The pinion is thrown out of gear 
by removing the pin out of the fork, and pushing 
the lever outwards, when the pinion will slip off 
the end of the crank-shaft. When in situ, the upper 
pinion gears into a tooth-wheel fixed on an axle, 
which carries a pinion placed outside of itself: this 
latter pinion gears direct into the tooth-wheel fixed 
on the axle of the road-wheel. It will be noticed 
that the intermediate tooth-wheel and pinion re- 
volve together upon the same axle, supported in 
bearings contained in a sheet-brass frame of No. 20 
metal, attached to the sides of the fire-box. This 
frame is open above and below, but for appearance' 
sake a tin cover is put over the tooth-wheels. 

All the tooth-wheels and pinions required may 
be obtained from any watchmaker. They must be 
fixed up to revolve in the frame upon the engine, so 



184 MODEL ENGINE CONSTRUCTION 

that they do not lock when the road-wheels rest on 
the ground, and the engine is set to work. The 
above is not the arrangement of the gearing in a 
real engine, but it is easily fitted up, and works 
well. 

The tender and spirit-lamp. The tender is small, 
of a width a little more than that of the fire-box. 
It had best be cut out of tin plate (tin from an 
old biscuit-box does well where a thin plate is 
required) to the correct size, then bent over a 
block by hammering to shape it out. The tender, 
or bunker, is composed of a floor, a back, and 
two sides. These last should have each in front 
a flange made to project inwards, so that when 
the tender is fitted to the engine, the flanges 
project inwards against the sides of the fire-box, 
and are fastened to it by solder. Along the upper 
border of the back, and each of the sides, solder 
on a coping. This is made of a single strip of tin, 
or separate pieces are joined together at the angles. 
After being bent to the proper shape, solder an iron 
wire around the tender to rest on the upper edges 
of the sides and back, as this, combined with the 



TRACTION ENGINE. 185 

coping, gives a good appearance when finished. The 
foot-plate is cut out with the tender from the same 
sheet, or else is soldered all round to the lower edges 
of the back and sides. On one side two brackets are 
soldered for the brake-rod, and two steps are cut 
out of sheet brass and fixed on, as in a real engine. 
The draw-bar consists of two sheet-brass angles, 
soldered behind the tender close to each other, with 
a bolt passing through a hole drilled in the centres 
of both of them. 

The lamp is made of tin, as described on page 51. 
The tank is rectangular, of the same length and 
width as the tender, and it can be made square or 
circular at the back : the latter is the best (see 
working drawings), as then, with the filler, it repre- 
sents the water-tank in a real engine. The sides 
of the lamp, as well as the back, must be prolonged 
upwards to meet the tender under the foot-plate, 
and the top border of each side must be bent 
inwards for about -§-" : this is to enable the lamp 
to be drawn out and in, along a horizontal groove 
under the foot-plate (see working drawing sheets). 
The groove is made by soldering on both sides, 
under the full length of the foot-plate, a piece of 



186 MODEL ENGINE CONSTRUCTION. 

cranked tin, so that the internal collar of the sides 
of the lamp passes in between the foot-plate and 
this cranked piece of tin. In order to be under- 
stood, we have exaggerated all the angles shown in 
the drawings of the lamp. The funnel for pouring 
in methylated spirits to the lamp is fixed at the side 
of the lamp and the tender. It is D-shaped in 
section, with the flat part close to the tender, and 
the convex part bulging outwards. It can be fitted 
on the top with a lid, hinged to it, and in this way 
it represents the inlet to the tank in a real engine. 
The steering-wheel is of brass, fixed on a wire shaft, 
that carries a bevel-pinion at its other end. This 
rod passes through two bearings, simply pieces of 
sheet brass soldered to the sides of the fire-box ; a 
small brass ring is soldered above and below the 
bearings, to keep the pinion at the end in contact 
with the other one. 

The brake (see working drawings) is entirely for 
appearance' sake, and to give a finish. It is placed 
on one side of the tender only. The brake-rod 
(of iron wire) passes through two stiff sheet-brass 
brackets, soldered on the side of the tender. The 
rod is kept from vertical movement by the brake 






TRACTION ENGINE. 187 

handle, which is firmly screwed and soldered on the 
top of the rod, and a collar is soldered on under- 
neath the upper bracket. A lever passes along 
from this rod, at right angles to it, and operates on 
the brake by tightening a brass strap up against a 
pulley which revolves with the road-wheel, and is 
fixed to its central boss. This lever is again acted 
upon by a pivoted nut, through which the brake-rod 
passes. In this nut, the vertical hole for the rod 
and the horizontal one for the pivots should be 
drilled in line with each other, but in a small size 
there is difficulty in getting a sufficient amount 
of metal on the sides of the central hole for the 
pivots to grip, so that it is better to drill the 
vertical hole either in front or behind the horizontal 
hole. In this way the nut will act just the same 
in operating on the brake, and the pivot can be 
formed by a copper rivet passing through the forks 
and the nut, and riveted on both sides : the vertical 
hole must be tapped by a suitable thread to fit 
the screw on the brake-rod. This screw, though 
capable of being freely turned by the handle, cannot 
lift, and will therefore raise or depress the nut 



188 MODEL ENGINE CONSTRUCTION. 

and its lever. The strap is a strip of sheet brass 
pivoted at one end of a fulcrum, and passing about 
half-way round the pulley before being embraced 
by the end of the lever; this strap can be drawn 
tight on the pulley, or left slack, according to 
the direction in which the brake handle is turned. 
The brake might be connected with both road- 
wheels, but this would involve more labour, and its 
attachment to one wheel is quite sufficient. 

Cotton wicks do for the lamp, but wicks of 
asbestos twine give better results, for if the spirits 
of wine falls short, this substance does not burn 
away like cotton, and on pouring in more spirits, 
the fire soon gets brisk again. The above is a 
description with drawings of an engine as made 
by the author, a short account of which he gave 
in the English Mechanic some years ago. The 
engine in working order weighs 3f lbs. fully. It 
will travel slowly backwards or forwards along a 
smooth floor, and haul a load; it will also mount 
a slight incline, consisting of a plank a little inclined 
at one end. When at work, the fire-door should be 
left open for admission of air to the lamp. We 



PORTABLE ENGINE. 189 

omitted to state that the side-plates which carry 
the crank-shaft bearings are made of sheet brass, 
one fixed on each side (by solder) to the fire-box. 
There is a tin cross plate between them in front, 
which fits the curvature of the boiler underneath, 
and which contains two slots, one for the connect- 
ing-rod to pass through, and the other for the 
eccentric-rods : this is called the " spectacle plate." 
It may be omitted, as it is troublesome to fit up. 

Portable engine (see Fig. 52 and Sheet No. 9). 
This form of engine will not detain us long in de- 
scribing, as it resembles the above, but the cylinder 
is set over the fire-box, and not at the smoke-box 
end of the boiler. There is no link motion and 
tooth-wheel gearing to fit up. As the engine is 
stationary when at work, the road-wheels can be 
turned and finished on the lathe from brass cast- 
ings : their weight does not matter. The front 
wheels are attached to a pivoted frame below the 
smoke-box, as in the traction engine. The cylinder 
is set near the fire-box end of the boiler, and the 
fly-wheel at the smoke-box end. The brass bearings 
for the crank-shaft are bolted by their feet to stiff 



190 



MODEL ENGINE CONSTRUCTION. 






sheet-brass brackets, soldered to the sides of the 
boiler, as is done by some of the makers of portable 
engines. The safety-valve, -J" diameter, is fixed on 
the boiler at the side of the cylinder slide-valve case, 




Fig. 52. — Perspective view of Portable Engine. 



and connects with a small spring-balance pivoted to 
a bracket, which is soldered or screwed to the back 
of the boiler. A cock inserted between the steam- 
pipe and cylinder does duty as a regulator. The 



PORTABLE ENGINE. 191 

mouth of the steam-pipe inside the boiler should 
be turned up slightly, as in the traction engine. 
There is a screw-plug through which the boiler 
is filled with water ; the exhaust-pipe comes out 
underneath the cylinder, and is led along the top 
of the boiler, and inserted into the base or lower 
part of the funnel : the mouth of the blast-pipe 
here, as well as in all the other engines, should 
be flattened a little with a hammer before fixing 
it in position, as this contracts the opening, and 
causes a stronger blast or rush of steam through 
the funnel, thereby intensifying the draught. If 
the pipe be too much contracted at the mouth, 
this tends to increase the back pressure in the 
cylinder, and prevents the engine from working so 
well. A hole should be drilled leading into the 
slide-valve case, which can be made steam-tight 
by a small cock or screw-plug, for the purpose of 
oiling the parts inside and blowing out the water 
at the start, or if the engine primes. This is used 
instead of putting on cylinder cocks, which are 
difficult to fit, being so small. There is only one 
eccentric, which is set to run forwards. 



192 MODEL ENGINE CONSTBUCTION 

The lamp is made of tin, rectangular in shape, 
supporting eight or more wick-holders : there is a 
funnel through which to pour in spirits of wine. 
The lamp passes inside the fire-box, and rests on 
two long narrow sheet-brass strips, one near each 
end : these pass across from one side of the fire-box 
to the other, and are bent up outside at right angles, 
and riveted to the sides of the fire-box below the 
water-line. 

The funnel can be made in one portion, or in two 
separate pieces, and hinged together. It may be 
made of brass tube, tin, or sheet brass. This last 
can be hammered over a circular piece of wood till 
it forms a tube ; the longitudinal seam may then be 
soldered, and a rivet put through at the top and 
bottom : this will hold it firmly together. The 
lower part or base may be a brass casting, or be 
made of sheet brass : then it ought to have a collar 
turned down upon it, and be fixed by two rivets 
over a suitable aperture on the smoke-box. 

For details of chimney hinge, refer to Sheet 
No. 9. Cut out two pieces of sheet brass to size 
and shape shown (see Fig. 1), slot out one of the 



PORTABLE ENGINE. 193 

pieces, so that A will fit inside space B quite easily, 
bend each piece to the same curvature as the funnel 
(see Fig. 2) ; the projecting or narrow portions A 
and B will now stand pointing upwards and down- 
wards, when the free edges of the semi-circular 
portions are placed against each other. With pliers 
bend both A and sides of B at right angles to the 
semi-curved portions, fix one of the pieces to the 
back of the root of the long portion of the funnel, 
by slipping a small ring over it and the funnel (a 
picture ring will do), solder the parts together (the 
ring prevents the parts getting loose if the heat 
melts the solder), attach the other piece to the 
upper part of the lower portion of the funnel with 
a small ring in the same way, and solder them 
together ; each portion of the funnel has half of 
the hinge attached to it. To fasten them together, 
with pliers bend the end of A into a circle, and 
do the same with the edges of B : see that they 
fall in line with each other, and A will lie inside 
B. Now push a small bolt through B and A (see 
Figs. 4 and 5), with a head on one side and a nut 

on the other, and the hinge is complete. If a small 

o 



194 MODEL ENGINE CONSTRUCTION. 

strip of sheet brass, about -J-" deep, is bent circular 
and riveted together, so as just to pass inside and 
be a tight fit within the lower portion of the funnel, 
on raising the upper portion to the vertical position 
it will slip over the collar and be kept quite steady. 
The hinge should be so fixed that the funnel will 
hinge backwards and rest on a brass fork (a casting) 
screwed into the valve-chest. There is no cap on 
the funnel, which all portable engines have. This is 
omitted, as small boilers do not steam well with one, 
for it contracts the orifice of the funnel, and the fire 
burns badly. The outer fire-box and boiler barrel is 
made of No. 24 sheet copper, the internal fire-box, 
fire-tube, and tube-plate of No. 21 sheet copper. 

Semi-portable or underneath engine (see Fig. 53 
and Sheet No. 10). This engine is made by placing 
a locomotive boiler on the top of a flat-bed en- 
gine ; a support or saddle-plate is fixed above the 
cylinder for the smoke-box to rest upon. The bed- 
plate is a brass casting, or is made out of No. 20 
sheet brass, and riveted together. In real engines, 
the cylinder, steam-chest, stop-valve chamber, and 
saddle-plate are combined in one casting. As this 



SEMI-POBTABLE ENGINE. 



195 



would involve special patterns, and be troublesome 
in a model, we take the steam by means of an 
outside pipe leading to and screwed direct into the 
valve-casing, the exit from the boiler being con- 
trolled by a cock or a stop-valve. The steam-pipe 




Perspective view of Semi portable Engine 
Fig. 53. 



inside the boiler (see Sheet No. 10) is bent at right 
angles, its mouth being plugged, and a number of 
holes drilled in the upper surface for steam to enter, 
and in this way dry steam is got, instead of using a 
dome. The saddle-plate is a brass casting, either 
cast on the cylinder or, if separate, firmly soldered 



196 MODEL ENGINE CONSTRUCTION. 

all round to it and to the valve-casing. The under 
surface is flat, the upper surface is cast with the 
same curvature as the bottom of the smoke-box, 
and supports it, this last being attached to it at the 
sides by small bolts and nuts. Before fixing the 
plate, a hole should be drilled vertically through it, 
one end communicating with the cylinder exhaust- 
port, and the other tapped to take the blast-pipe 
which passes up to about the middle of the fire- 
tube in the smoke-box (see drawings). Make the 
bed-plate — if it is to be a built-up one — of four 
pieces of stiff sheet brass, two forming the side 
girders, and two the end ones. The side girders 
are flanged outwards on the top, secured to the end 
pieces by angle brass inside, and riveted together 
perfectly square. At the foot, a piece of angle brass 
is soldered or riveted all round to the frame, except 
upon one side, for a short distance, to give room for 
the fly-wheel to pass through. The bed-plate is 
fixed by screw-nails, that pass through the flange 
to a wooden block or stand. Two sheet-brass cross- 
pieces, each of the same depth, are riveted inside 
between the frames (see drawings), to act as stays. 



SEMI-PORTABLE ENGINE. 197 

No longitudinal central girder is required, for the 
frame will be stiff enough without. A thin brass 
plate passes across the girders from the smoke-box 
end to the first cross-stay, and this is soldered or 
riveted to the side flanges : the cylinder and guide- 
bars are firmly bolted down to this plate. The 
guide-bars are four in number, fitted up in the 
same way as for the horizontal engine. The two 
bearings for the crank-shaft are placed near the 
fire-box end of the boiler (see drawings), and are 
bolted to the flanges of the side frames or girders. 
The fire-box is open underneath, rests upon and is 
fastened by means of angle brass and bolts to the 
flanges of the side frames and cross-piece at the 
back of the fire-box. The boiler must be raised 
so high that the crank and connecting-rod may 
keep clear of it when revolving. There is a spring- 
balance safety-valve on the boiler, and a plug for 
filling it with water. There is only one eccentric, 
set for forward motion. The wooden frame must 
be slotted out for the fly-wheel to pass through on 
one side. The outer fire-box and barrel is made of 
No. 24 sheet copper, the internal fire-box, fire- 



108 MODEL ENGINE CONSTRUCTION. 

tube, and tube-plate of No. 21 sheet copper, and 
frames of No. 20 sheet brass. 

A more powerful working engine, and one more 
easily fitted up, can be made by doubling the dimen- 
sions over all, or nearly so, of that on Sheet No. 10. 
Make the boiler, the same as described on page 46, 
of No. 16 sheet brass and No. 18 sheet copper : all 
the joints must be brazed. The cylinder is 1" bore, 
2" stroke, which along with the saddle-plate, fly- 
wheel, and bed-plate may be made from brass or 
iron castings; but brass, being softer than iron, is 
the easiest of the two metals to work, and is not 
liable to crack when being drilled, like iron. The 
bed-plate may be a casting, fully -fa" in thickness, 
or built up of longitudinal girders composed of 
No. 16 sheet brass : a slot must be cut out for the 
connecting rod "big end" and crank to pass when 
revolving. The boiler rests at the fire-box end, 
and is attached by angle brasses ; screws fasten the 
bed-plate to a wooden sole-plate. The force-pump 
described on page 71 will be suitable for this 
engine. And if a small gas-jet is burned inside the 
fire-box, the engine will work away for an hour or 



SEMI-PORTABLE ENGINE. 199 

two at a time without much attention, if the pump 
is regulated so that a constant water-level is main- 
tained in the boiler. The bearings are entirely of 
brass. The crank-shaft must be a forging. A y\" 
cock will be large enough to supply the cylinder 
with steam, through a pipe of the same bore. 



CHAPTER VIII. 

LOCOMOTIVE ENGINE AND TENDER. 

We will describe in detail the making of a loco- 
motive engine, in such a manner that little difficulty 
need be experienced in the construction of any of 
the several forms illustrated in this work. There is 
considerably more labour involved in a locomotive 
than in any of the engines hitherto mentioned. It 
includes a boiler, with a pair of cylinders, fitted with 
reversing-gear, and all the motion work connected 
with the engines must be carefully fitted and ad- 
justed, so as to work satisfactorily under steam when 
made. The locomotives we propose taking up, 
though perhaps not just " correct models " in every 
minute detail, will be found to be exact semblances 
to the real thing, work well under steam, and be 
superior to any of the cheaper slide-valve locomo- 



LOCOMOTIVE ENGINE AND TENDER. 201 

tives sold in the shops, approaching in their con- 
struction the "powerful models of modern loco- 
motives " as sold by Mr. Lee and others, and which 
from their high prices are beyond the reach of the 
ordinary amateur. The construction of any of the 
locomotives may be undertaken by an amateur of 
ordinary ability, without heavy or costly tools, and 
with every reasonable prospect of accomplishing it 
in a satisfactory way, provided he has patience to 
carry out the task to the end. These small loco- 
motives will require accurate workmanship to ensure 
success, but the work is very light, and when 
finished, if carefully made, they will run well upon 
rails. If any one would like to construct a more 
powerful locomotive, let him refer to page 239, and 
to Sheet No. 13 ; these working drawings are so 
proportioned, that by doubling the dimensions over 
all, or nearly so, a large and powerful model can 
be made. 

All the locomotives have coupled driving-wheels, 
except in one instance : they have single frames 
(with or without bogie), and outside cylinders, set 
parallel with the axis of the boiler. We have 



202 MODEL ENGINE CONSTRUCTION. 

adopted outside cylinders, as inside cylinders and a 
crank-axle are difficult to fit up, for want of room, 
between the frames ; and the axle, being small, 
must be a "built-up" one, and probably would not 
last very long if run often. 

This locomotive (see Sheet No. 11, A, B, C) is 
called a bogie locomotive, as the front part of the 
frame and smoke-box rests upon a four-wheel truck. 
All the dimensions can be got by referring to the 
working drawings. 

The frames are made from No. 20 sheet brass, 
and form the attachment for the fittings. They 
receive and sustain all the stresses due to the 
moving parts ; they are supported on the journals 
of the axles, and carry the boiler, with the cylinders 
and valve-gear. The two side frames, or frame- 
plates, are made of stiff sheet brass rather than 
a casting, to save weight, mark and cut to outline 
(see drawings). Both frames are attached in front 
to a wooden buffer-beam A, by means of sheet- 
brass angles, on one side only, riveted or soldered 
to the frames by copper wire rivets, and attached 
to the beam b}^ very small bolts and nuts. At the 






LOCOMOTIVE ENGINE AND TENDER. 203 

back they are held together by a transverse sheet- 
brass plate B, in length equal to the buffer-beam. 
Care must be taken that the side frames and the 
end ones are at right angles to each other. To 
stiffen the frame, two cross-stretchers, C, D, are 
riveted inside by angles, one passing in front of 
the fire-box, and the other behind the cylinders. 
This last is called the "motion-plate," and to it 
the slide-valve spindle-guides are fixed in a real 
engine; but here this plate is simply slotted out 
near both ends, to allow the slide-valve spindles to 
pass through. A drag-plate casting at the hinder 
end is omitted to save weight, as well as axle- 
boxes, horn-plates, and springs. The straight axles 
simply pass through holes drilled in the side-plates 
to receive them; the rectangular holes slotted out 
in the front part of the frames on each side, over 
the bogie-truck, are to take the steam-chests of 
the cylinders, which are thrust through them, the 
cylinders being outside the frames, and the valve- 
chests inside. Underneath the cylinders a trans- 
verse stay passes from one frame to the other, and 
is attached to each of them by rivets; the under 



204 MODEL ENGINE CONSTRUCTION. 

surface of this stay forms the support for the bogie- 
truck, which rests against it ; a pin passes through 
the centre of the stay and the bogie-truck, on this 
the latter pivots ; a nut on the under surface of the 
bogie-pin completes the attachment. The buffers 
are all four of brass, turned on the lathe ; the front 
ones, corresponding with those on the back of the 
tender, are larger than those on the hind frame 
of the engine. Each of them is centred, tapped 
with a thread, and a screw put through, by which 
they are attached to the frames. The screws pass 
through the buffer-beam and hind frame, and 
tighten up the buffers with nuts. It will thus 
be seen that the buffers are solid, and have no 
springs. 

The bogie consists of a rectangular frame made 
of No. 20 sheet brass, flattened by hammering, and 
riveted together. There is a central pivot-hole, 
drilled in a transverse stay, riveted on to the top 
of the frame, through which the central bolt passes. 
The holes for the axles are simply drilled through 
the sides of the frames, at a distance of 2-J" from 
each other ; there are no springs. The cow-catchers 



LOCOMOTIVE ENGINE AND TENDER. 205 

are made of sheet brass, and riveted on to the 
sides in front, so as to project before the wheels, 
and keep clear of the rails. 

The wheels. Those of the bogie are four in 
number, of cast brass, turned and faced on the 
lathe. They are 1 T V' diameter on the tread, and 
are screwed firmly upon straight axles, which have 
been previously turned in the lathe. They, and all 
the other wheels, must be bored straight through 
the centres, and fixed so as not to wobble, but re- 
volve truly on their axles. The driving-wheels, four 
in number, are made from castings. It is necessary 
to turn the wheels on the lathe, and this can be 
done by drilling them, after correctly centering, 
and mounting them on a temporary shaft be- 
tween the lathe-centres : turn them on the treads, 
flanges, rim, boss faces, and edges. All the wheels 
should be slightly coned on the tread, and the 
flanges of them all thinned down on the lathe 
to just over -£%" in thickness, as this diminishes 
fiiction. The spokes can be filed smoothly over, 
and painted afterwards. The axles for these wheels 
are straight ones, made of iron wire fully -|" thick, 



206 MODEL ENGINE CONSTRUCTION. 

cut to the correct length, tapped with a screw, and 
the wheels firmly screwed on to them. It is a good 
plan to turn the ends of the axles where they enter 
the boss of the wheels to a smaller diameter, as 
in this way a collar is left, upon which the wheels 
can be screwed up tight, and are likely to remain 
so. Without this arrangement, especially where 
reversing-gear is put on and the wheels run in both 
directions, they are apt to shift on their axles, 
from the thread of the screw getting slack, which 
must be prevented from occurring. The bogie- 
wheels can be fixed in any position on their axles, 
but the driving-wheels must be firmly fastened, 
so that the crank of the one wheel is set at right 
angles to the other crank upon the same axle. The 
driving-wheels could be fixed firmly on their axles 
by means of a small set-screw, a hole for which 
has been drilled upon the inside projecting boss 
of each wheel, running at right angles to the central 
hole for the axle. This plan does well if the screw 
is made fairly strong, and it can be tightened up 
with pliers after the wheel is on the axle. 

The coupling-rods pass between the driving- 






LOCOMOTIVE ENGINE AND TENDER. 207 

wheels. They are made of soft iron, and filed to 
outline T V' thick and 4 T V' between their centres ; 
they are not bushed with brass, the holes for the 
cranks being simply drilled through them. These 
rods rest upon plain crank-pins screwed into the 
boss of the wheels, and are kept on by nuts which 
screw up against a collar on each pin. This collar 
is made by making the end of the pin which enters 
the nut a size smaller than the body of the pin, 
and tapping it with a thread. The nut could be 
soldered on, but this is not handy, if it be required 
to take the rods off at any time. The crank-pin of 
the driving-wheel is the same, but longer, than 
that on the trailing-wheel, and passes through both 
the connecting-rod and the coupling-rod at the 
same time. 

As some amateurs may prefer to have axle-boxes 
fitted on the frames, which are wanting in the above 
locomotive, we will mention how these can be ap- 
plied, at least for the driving-wheels. Make the 
axle-boxes of undivided rectangular blocks of brass 
(see Sheet No. 11, C), to suit straight axles ; these 
fit and slide between the horn-blocks B, and being 



203 MODEL ENGINE CONSTRUCTION. 

flanged, slide upon the faces of the horn-blocks on 
one side, and of the frame-plates A on the other; 
the holes for the axles are drilled through the solid 
boxes. The horn-blocks are cut out of No. 20 
sheet brass, of arched form, and are fastened to the 
frame-plates by small rivets or solder. The axle- 
boxes C must be fitted by filing to be an easy 
sliding fit between the faces of the horn-blocks and 
the frame-plates; file the outer faces of the horn- 
blocks smooth, to be an easy fit with the guide- 
strips of the axle-boxes. It is best, for small 
engines, to adopt spiral wire springs. The spring 
enters a shallow hole drilled in the top of each 
axle-box ; it bears between the bottom of this hole 
and the lower face of the arched horn-block : small 
horn-stays pass across the foot of the horn-blocks, 
and are kept in place by screws or solder. To 
diminish friction, the axle-boxes must not be more 
than 3^" in thickness, and if adopted, a wider gauge 
of line will be required than 2-^f-". 

The cylinders are fitted up as described on page 
79. Each cylinder has only one circular guide-bar 
(of iron wire), screwed into the back cover at the 



LOCOMOTIVE ENGINE AND TENDER. 209 

top part, to save friction. The free end of the 
guide-bar is left loose, and is not attached to the 
frames, but it might be so fastened. The cross-head 
is forked, and has a long projecting guide, which 
embraces the guide-bar (see dotted lines in Sheet 
No. 11, A). It is a good plan to screw into each 
valve-chest a small cock through which oil can be 
poured, or even injected, to oil the slide-valve and 
piston each time before running the engine, as this 
tends to diminish friction, and the engine runs more 
easily. When in position, the steam-chests of each 
cylinder are connected together by means of a hori- 
zontal pipe passing between them, and they are so 
placed that the chests lie in the rectangular holes in 
the side frames, while the cylinders are outside ; and 
if flanges are not cast on the cylinders for attaching 
them to the frames, these must be made of sheet 
brass, and soldered round the steam-chests outside 
the frames, and attached to the latter by bolts in 
order to give rigidity to the cylinders, and prevent 
them from rocking. Be careful, when fitting, that 
the centre of each cylinder is at the same distance 

from the centre of the driving-axle, and that the 

p 



210 MODEL ENGINE CONSTBUCTION. 

central line of the axis of the cylinders, if prolonged, 
would pass through the centres of the driving- and 
trailing-wheels, and also be at right angles to the 
axle, and quite parallel with the frames. 

The pistons are of brass, \" broad, having a \" 
groove for packing, with a T V' collar on each side 
of the groove. 

The connecting-rods are made of soft iron, and 
have solid ends ; but if preferred, the " big ends " 
can be made as described on page 97. 

Valve-gear. The slot-links are made of sheet 
brass, similar to that on the traction engine (see 
page 172). The lifting-links (of sheet brass) are 
two in number, one for each slot-link, placed upon 
the outside only. Each pivots upon a short arm, 
which is riveted immovably upon a central snug on 
the slot-link (see page 172), or these could be at- 
tached to a snug upon the lower end of the link in 
the line of curvature, and be fixed to it by a small 
bolt passing through both, and fastened with a nut. 
There are four eccentric-pulleys on the driving- 
axle, two set for forward and two for backward 
motion. The eccentric-straps can be made of sheet 



LOCOMOTIVE ENGINE AND TENDER. 211 

brass, the rods of brass wire, and the forked ends 
cut out of solid brass and screwed to the rods ; the 
bolt on which the ■ link pivots is fastened to them 
with solder. For their construction see pages 116, 
137, and 139, also Sheets No. 11, C, and No. 8, C. 

The weigh-bar passes across under the boiler from 
one frame to the other, being supported in sheet- 
brass bearings soldered to the frames. There is a 
small lever on each side to pivot to the lifting-links, 
and a rod passes along at the side of the boiler, 
inside the splashers, to a reversing-lever moving in 
a notched quadrant placed on the foot-plate (see 
longitudinal section of locomotive, Sheet No. 11, A). 
The reversing-lever and quadrant are placed on the 
left-hand side of the foot-plate. The travel of the 
slide-valve is ^-", the steam-ports are -j^" -f \", and 
the exhaust-port 3%" + J". 

The boiler is made of No. 24 sheet copper, and 
all the dimensions will be found on Sheet No. 11, A. 

The internal fire-box is made of No. 21 sheet 
copper, and must be brazed. For the method of 
making it, see page 37. We employ thinner copper 
for the outside of the boilers, in order to render 



212 MODEL ENGINE CONSTRUCTION. 

them lighter than they would be if the whole was 
made of No. 21 sheet copper. 

The regulator is a cock attached to the steam- 
pipe in the smoke-box after it emerges from the 
boiler. This cock is opened and shut by a small 
wire which passes through a ^t" bore brass tube, 
soldered into each end of the boiler near the top. 
One end of this wire is pivoted to the regulator 
handle on the back of the boiler, which moves on 
a pivot in the ordinary way. When this handle is 
pulled out by one end, it opens the cock, admitting 
steam to the cylinders ; and when pushed in close to 
the boiler, shuts the cock. The smoke-box end of 
the wire is bent downwards so as to form a kind of 
loop, which embraces the crank-shaped handle of 
the cock (see Sheet No. 11, B). The wire is of such 
a length that when the regulator is (shut) close to 
the boiler, the cock handle is pushed out near the 
smoke-box end and closed ; and when the regulator 
is pulled out, the cock handle is drawn towards the 
end of the boiler and is then open. Putting this 
wire through a ^" bore tube saves making two 
stuffing-boxes at the ends of the boiler for it to pass 



LOCOMOTIVE ENGINE AND TENDER. 213 

through, as these, being small, are difficult to con- 
struct and keep steam-tight. A coupling-screw 
connects this cock to the vertical pipe underneath, 
that joins the horizontal pipe passing between the 
cylinders; the cock at its upper orifice is screwed 
to the steam-pipe which passes out through the 
tube-plate (the steam-pipe is soldered to the tube- 
plate). Of course a vertical opening for steam to 
pass through must be made in the horizontal tube, 
before the vertical one is soldered to it. Inside the 
boiler, the steam-pipe is carried along and passes 
up inside the dome; it is simply pushed through 
the tube-plate and soldered : there is no support 
required for the pipe inside the dome. There is 
only one steam-pipe, but two separate blast-pipes. 

The safety-valve is made of brass, and instead of 
being fixed on a separate casing it is mounted upon 
the dome. This is a brass casting which must be 
turned on the lathe, and in order to chuck it the 
dome should be centre-punched at the top, driven 
tightly upon a turned piece of hard wood, then 
fixed between the lathe-centres, and turned down to 
the correct size. After this, drill two holes through 



214 MODEL ENGINE CONSTRUCTION. 

the top, into which two brass pillars are fixed. 
These are made of pieces of brass tube screwed into 
the dome : one of them forms the fulcrum, and is 
slotted out for the lever to pass through — its orifice 
is plugged underneath — the other pillar forms the 
valve proper, and communicates with the interior 
of the dome. Upon it a valve-seat is formed, about 
\" diameter, and a valve is turned to fit the seat. 
The lever, cut out of sheet brass, is pivoted to one 
pillar, and passes through a longitudinal groove in 
the top of the valve as it rests in the other pillar. 
A small spiral brass spring, which can be procured 
from any watchmaker, holds the lever down upon 
the valve, being so placed that its coils fill the space 
between an eye-bolt and the lever (the stem of 
which passes through the dome, enters a nut, and 
is soldered inside). One end of this spring is bent 
round and inserted into the small ring or eye-bolt, 
and the other into the eye of the lever ; the fitting 
of this spring is rather difficult, but can be done 
with a little trouble. The valve has the appearance 
of the " Ramsbottom type," and if properly made it 
will act; however, we advise a direct-acting spring 



LOCOMOTIVE ENGINE AND TENDER. 215 

safety-valve to be attached to the boiler over and 
above, which can be relied upon to blow off excessive 
pressure of steam. 

See Sheet No. 11, A, for back view of the loco- 
motive with fittings. There is a fire-door, made of 
sheet brass, with hinges and a latch. These are 
riveted to the door, but soldered to the boiler. The 
regulator handle is pivoted horizontally to a piece 
of angle brass, soldered to the boiler on one side of 
the middle line, and on the other embraces the 
rod coming from the cock in the smoke-box, and is 
made of iron wire. There is no water-gauge, force- 
pump, or pressure-gauge attached. Two small cocks 
are soldered into the boiler to ascertain the height 
of the water ; these should be purchased ready 
made. For description of reversing-gear see page 
137, and Sheet No. 11, C. 

The cab is made entirely of thin sheet tin. The 
top and the sides are in one piece ; the saddle-plate 
arches over the back of the fire-box, and fits closely 
around it. The sides of the cab are bent circular 
with the top arching over the foot-plate, and are 
cut to a curved shape, so as to rest upon the 



216 MODEL ENGINE CONSTRUCTION. 

top sheet of the hind splashers, and be soldered to 
them as well as to the saddle-plate. To strengthen 
the joints, three brass angles can be soldered on 
inside, between the cab sides and top, to the saddle- 
plate. A hand-rail pillar, made of wire, is soldered 
to the splashers and to the sides of the cab, and 
joins them by a strip of sheet brass which embraces 
the hand pillars. The windows are made by drilling 
two T V' holes in the saddle-plate, inserting glass 
discs — microscopic cover-glasses, f" diameter, do 
well, and can be had from any optician. These 
discs rest against the edges of the window aper- 
tures in the saddle-plate, and around their edges 
a thin ring of tin plate, slightly overlapping, is 
soldered all round to keep them fixed. The foot- 
plate is the floor-space from the back of the framing 
up to the fire-box, and is fitted between the inside 
back splasher-sheets, to which it can be soldered. 
The splasher-sheets are made of tin, consisting of 
outside pieces and a top ; there are no inside 
splashers, except over the back or inside half of the 
trailing-wheels, to conceal them from the foot-plate. 
Upon each side there is only a single splasher for 



LOCOMOTIVE ENGINE AND TENDER. 217 

the two wheels (see Sheet No. 11, B). This saves 
much work in fitting, and is adopted on the North- 
Eastern Railway. The splashers rest upon the 
side-plates of the engine : a piece is cut out on 
the under surface to let the coupling-rods pass 
without striking the sides ; an angle piece, in 
section like Z> passes along the entire length at 
the foot, and by it the splashers are fastened with 
bolts and nuts or solder to the side-plates. The 
top sheet is of tin, fastened to the splasher sides 
with solder by one edge, and by its other rests 
against the boiler. 

Front view of locomotive (see Sheet No. 11, A). 
The smoke-box door is circular in shape, made of tin 
plate, but not dished; small hinges are riveted to 
it and to the smoke-box. The door is secured with 
a bar and a T-headed bolt moved by the handle. 
The buffers are screwed into the buffer-beam, and 
secured by a nut. 

The drawings (Sheet No. 11, A) show the smoke- 
box in section from the front. On the left hand 
the section passes through the steam-pipe, on the 
other through the exhaust-pipe. The steam-pipe is 



218 MODEL ENGINE CONSTRUCTION. 

common to both cylinders. The single fire-tube is 
seen opening into the smoke-box, in front of which 
the steam-pipe, -§" bore, and the cock pass, being 
attached by means of a coupling-screw to the 
vertical pipe, which is soldered to the horizontal 
pipe passing between the cylinders. The object of 
having a coupling-screw in this pipe is for the 
purpose of being able to remove the boiler from the 
framing, if it is required to do so. The horizontal 
pipe is screwed or soldered into the steam-chests. 
The blast-pipes are screwed each into the openings 
of the exhaust-ports ; they are bent inwards, and 
cut short so as to stand no higher than the middle 
of the fire-tube, as this height for their nozzles 
gives the best draught. Their mouths are flattened 
to contract their orifices, and so intensify the 
draught. 

The boiler is attached to the frames by the 
coupling-screw at the smoke-box end, as men- 
tioned above ; and in front, on its under surface, 
the barrel rests on the concavity of a vertical piece 
of tin passing between the frames, and this forms 
the under surface of the back of the smoke-box 



LOCOMOTIVE ENGINE AND TENDER. 219 

(underneath the barrel). At the fire-box end the 
boiler rests on the side frames by brackets, which 
are not fastened to the frame-plates, and so allow 
of expansion : the brackets are soldered to the 
fire-box sides at a height to keep the boiler level. 
When the cab is firmly fixed, the boiler cannot 
shift. 

The smoke-box should be made so that it will 
push along the front part of the frames over the 
bogie on to the boiler, and pass as far back as to 
rest against the plate underneath the barrel, and a 
wire can be soldered all round the barrel as a finish, 
to fill up the space between it and the boiler. 
The smoke-box must be cut away for about three- 
quarters of its length on the under surface, to allow 
of being slid past the steam- and exhaust-pipes, and 
to close this opening a small tin plate may be put 
across under the smoke-box, between the frames, 
resting on the steam-chests, as the cylinders are not 
contained in the smoke-box. The smoke-box is 
fastened to the frames by a small bolt and nut 
on each side. The funnel is made of tin riveted 
to the smoke-box, set over an aperture made for it, 



220 MODEL ENGINE CONSTRUCTION. 

and a wire is soldered round the top. Sheet No. 11, 
A, gives the half-sections of the boiler as seen from 
the foot-plate and front buffer-beam ends, along 
with an elevation, longitudinal section, and plan. 
Sheet No. 11, B, gives plan of the engines, the 
frame-plates, and numerous detail drawings. Sheet 
No. 11, C, is devoted to the tender, lamp, brake, 
and link motion. 

The foot-plate, with side-plates, had best be cut 
out of a single sheet of tin, and made so as to clear 
the boiler and driving-wheels when in position. It 
is attached by bolts to the angles on the top of the 
inside frames : it could be made in strips, cut out, 
and fitted all round outside. Angle-pieces had best 
be soldered on to each side of the projecting. plates 
along their whole length, to give a better appear- 
ance and finish to the engine. The steps for the 
driver to get on to the foot-plate are cut out of 
sheet brass : they hang downwards, being soldered 
to the insides of the side frames. 

The spirit-lamp is made of tin : the rectangular 
tank fits in under the foot-plate between the frames. 
It passes inside the fire-box, and rests upon two 



LOCOMOTIVE ENGINE AND TENDER. 221 

strips of brass riveted across near the front and 
back end : it carries twelve T V' wick-holders. A 
funnel is soldered into the end of the tank : this 
passes up inside the buffers (at the end of the 
locomotive) to about the height of the foot-plate, 
and spirits of wine is poured into this to feed the 
flames, through a corresponding hole cut in the 
flap cover-plate. When the tender is uncoupled 
from the engine, the lamp can be taken out as 
required. 

Having described the locomotive in detail, we 
now take up the tender, and refer the reader to 
the drawings on Sheet No. 11, C. There is a 
longitudinal view, with a longitudinal section down 
the centre of the tender. The lower half of the 
plan drawing is a half view of tender as seen 
from above. The upper half contains three plan 
sections : at A, the top and sides of the tank are 
removed, and we see the floor-plate B ; at C, the 
plate B is removed, and the view is taken on the 
angle D, which unites the framing and the floor- 
plate ; at E, the section is below this, through the 
centre of the front wheel and axle-bearings. There 



222 MODEL ENGINE CONSTRUCTION. 

is also a view of the front of the tender. The 
tender (to save weight) is made entirely of thin tin 
plate, and soldered together. The framing consists 
of two longitudinal frames cut to shape as shown ; 
the wheels are inside, and the axles simply pass 
through holes drilled in the frames. The distance 
from the centre of the back wheel to the front 
one is 5". The side frames are united at the ends, 
by means of angles, to two transverse stretchers : no 
intermediate bars are required, as the tender frame 
is stiff enough without them. On the upper edges 
of the side frames tin sheet angles are soldered, to 
carry the floor of the tank and coal-bunker, the 
wooden buffer-beam is attached to the hinder end 
(as in the locomotive) by the buffers, which are bolted 
to it and pass through the hind cross-stretcher as 
well, and are held in position by nuts. The tank 
is saddle-shaped, the sides are cut out of tin and 
bent to shape ; they are soldered all round to the 
floor, and to the sides of the tender in front. The 
cover-plate of the tank is soldered to the sides of the 
tank and tender. The filler is a screw water-plug, 
the seating of which is soldered into the top of the 



LOCOMOTIVE ENGINE AND TENDED. 223 

tank, over a suitable hole at the back part. At the 
front end a tin plate crosses from one tank side to 
the other, its upper edge, as well as the hole 
through which the coal is drawn, can have a wire 
soldered all round, to give a good finish. Two steps 
of sheet brass can be soldered to the frame-plates 
on each side. The coping is made of tin, bent and 
mitred at the hind corners, curved in front, and 
soldered all round to the sides ; a wire may also 
be soldered round the top to give finish, the hand 
pillars (of wire) are soldered into the plate at the 
bottom end, and to the curved support at the 
coping. 

The wheels are Ij" diameter, placed inside the 
frames. The axles are prolonged through them, and 
when in position rest in holes drilled in the side 
frames, and box-shaped covers of tin are soldered on 
(over the ends of the axles) to the outside frames, 
in order to represent real axle-boxes. The springs 
are pivoted at the ends, and soldered to the side- 
plates. These are only imitation springs, and put 
on for appearance' sake. They may be made from 
brass castings, or separate narrow strips of sheet 



224 MODEL ENGINE CONSTRUCTION. 

brass can be bound together by a brass strap 
and attached with solder, as is done in this case ; 
a wire hanger passes down from the centre of 
each spring, and rests upon the corresponding axle- 
box. Two buffers, similar to those on the back 
of the locomotive, are screwed into the front plate 
of the tender. A hinged sheet-brass eye-bolt is 
fixed between them, through which a hook attached 
to the engine passes, when the locomotive and 
tender are coupled together. 

The flap cover-plate F (see longitudinal section) 
covers over the open space between the tender and 
locomotive, to prevent the foot slipping between 
them. It is a strip of tin, flat or slightly curved, 
attached by a strap hinge to the tender foot-plate, 
and rests on the locomotive foot-plate when turned 
down. On one side there is a small hole drilled, 
corresponding with the position of the lamp-filler, 
and through this, when the locomotive is running, 
spirits of wine can be poured in to feed the wicks. 

The tool-boxes are made of tin, each having a 
hinged lid, and are soldered on the top of the 
tank. 






LOCOMOTIVE ENGINE AND TENDER. 225 

The hook, or draw-bar, is made out of a bit of 
wire, having a screwed shank which passes through 
the buffer-beam or hind frame, and is kept in 
position by a nut, a small brass collar having 
previously been soldered on it near the curve 
of the hook, to rest against the buffer-beam on 
the outside, when the nut is tightened up on the 
inside. 

There is no connection for water between the 
tank and the engine, but for appearance' sake a 
small brass tube, -J" bore, may be inserted at one 
side into the tank underneath the tender and 
soldered, being previously bent so as to project 
forwards. A cock can be inserted in the forward 
part of this pipe, with a wire stem passing up 
through the foot-plate, and turning in a little 
bearing soldered to the front of the tender, which 
is opened and shut by a small handle. A corre- 
sponding pipe can be attached to the engine and 
appear to communicate with the boiler (see Sheet 
No. 11, A), and rest against the tender feed-pipe, 
being in line with it when the latter is coupled 
up; and a piece of thin india-rubber tubing can 



226 MODEL ENGINE CONSTRUCTION. 

pass over the junction of the two pipes. One 
would suppose a coupling-screw might do, but this 
attachment is rather too rigid, and does not allow of 
sufficient play between the engine and tender. The 
pipe and cock may be entirely omitted. 

The brake (see Sheet No. 11, C). The pillar is a 
casting, or is made of stiff sheet brass, soldered to 
the foot-plate at one side, having a cross-bar on the 
top, and through the central portion of the cross-bar 
a hole is drilled for the brake-rod A. This rod is 
kept from vertical movement by a collar B, soldered 
on it below the cross-bar, and by the boss of the 
hand-wheel firmly fixed to it on the upper surface. 
The rod carries a screw near its lower end, and by 
means of the hand-lever raises and lowers a pivoted 
nut C, attached to the end of a bell-crank lever 
D, similar to that described for the traction engine. 
The bell-crank is made of stiff sheet brass, and is 
fixed on a brake-shaft, the bearings for which are 
in two brackets soldered to the under surface of the 
frame of the tender ; the lower end of the bell- 
crank is pivoted between the forks of the brake- 
rod, passing from the cross-shafts behind the front 



LOCOMOTIVE ENGINE AND TENDER. 227 

wheels. The remaining brake-rods correspond on 
the two sides, and the description of one serves 
for all. The hangers E are made of sheet brass, 
and are suspended inside the frames, and each has 
a horizontal brake-rod F, passing through to that 
on the opposite side. Each hanger is made of a 
strip of stiff sheet brass, having an eye at the 
top, which pivots in bearings soldered to the 
bottom of the tank floor. The brake-blocks G are 
made of hard wood, cut to suit the curvature of 
the wheel, and are fastened to the hangers by two 
pins of brass or iron wire, simply driven into the 
blocks through the hangers, which are amply suffi- 
cient to keep them tight. A horizontal rod H, 
pivoted to the lower ends of the hangers, connects 
all the brake-blocks together on one side. If 
this brake is well fitted, all the parts will move 
in unison on turning the brake handle, and it 
will act well. 

A screw-plug (to pour water in) is screwed into 
the top of the boiler, and there is a whistle ; the 
stem of the cock passes through the cab saddle- 
plate, and joins a handle above the boiler. On the 



228 MODEL ENGINE CONSTRUCTION. 

left side of the boiler (see elevation), a small block 
of brass with a pipe leading down to the side 
frames is attached : this represents the feed-pipe 
and clack-valve box in a large locomotive. 

There is no cleading around the boiler, i. e. strips 
of wood neatly fastened all round the boiler with 
brass hoops, to retain the heat, as this locomotive 
is rather small to have it. One or two sheet- 
brass rings may be soldered round the boiler to 
give a good finish. 

Spring buffers can be made as follows. The 
buffer itself is turned circular out of a piece of 
brass rod, and consists of a head and a stem ; the 
first is -J" diameter, the second is -J" diameter, 
and the whole is -f" long. In order to make plenty 
of room to get in a spring, drill a central hole 
fully j- 1 ^-" diameter, from the narrow end up to 
near the head, screw into the far end of this hole 
a wire spindle which has been filed to a narrower 
diameter all along the stem, slip a brass spring 
over this stem, of a size that will move freely in 
the central hole. Spring and wire must be then 
cut to the proper length. The buffer stem fits 






LOCOMOTIVE ENGINE AND TENDER. 229 

inside (with a telescopic motion) a turned brass 
casing, T V diameter and -§■" long, which is bored 
out to receive it, and is provided with a flange at 
one end, for attaching by two bolts and nuts to 
the buffer-beam. A central hole, scarcely T V' 
diameter, must pass through the flanged end of 
the casing, and communicate with the central 
aperture in the buffer. The pin that passes 
from the buffer goes through this hole when the 
buffer is placed inside the casing. The head of 
the spindle, being outside, moves backwards and 
forwards (in a wide, horizontal hole drilled to 
receive it through the buffer-beam) in response 
to the movements of the buffer against the spring 
in the casing. The head of the spindle coming 
in contact with the flanged end prevents the 
buffer from projecting too far out, or even being 
pulled out. The stem can be easily removed, when 
the buffer is unfastened from the buffer-beam, by 
simply unscrewing the spindle. The above plan is 
not the way the buffers are made in actual practice, 
but does very well, and is adopted as the easiest 



230 MODEL ENGINE CONSTRUCTION. 

way of making spring buffers when they are so 
small. 

The above is a description of a good working 
locomotive and tender, which was designed and 
made by the author, and from this engine all the 
working drawings were taken. 



CHAPTER IX. 

LOCOMOTIVE ENGINES. 

Bogie-tank locomotive (see Fig. 54 and Sheet No. 
12). A locomotive of this kind, having no tender 
to pull, will run along very easily. The method of 
its construction is similar to that of the last one, 
and being so we will not enter much into detail, 
but take up points on which it differs from that 
engine. 

The frames are made in the same way, but are 
longer, and are prolonged behind the foot-plate 
in order to carry the coal-bunker. This is made 
similar to the tender, with a coal space, separated 
by a cross-plate from the foot-plate, with an opening 
for shovelling out the coals in the centre. The 
driving-wheels are concealed from view above the 
side frames by the side tanks, which are only 



232 



MODEL ENGINE CONSTRUCTION. 



imitations and not real tanks for holding water: 
both are made of tin. Each consists of an outer 
plate, which by means of angles is bolted to the 
side frames; the ends (the front one fits the con- 
vexity of the boiler) and the top are soldered to 
the outer plate, the inner edges rest against the 
boiler barrel. An inside plate only extends from 




Fig. 54. 

the hind end up to the fire-box on the foot-plate 
at both sides. The sides of the cab are soldered 
to the top of the tanks, fitting over the saddle- 
plate in front. 

The lamp is made of tin, and this slides along a 
groove underneath the coal-bunker and foot-plate, 
between the wheel frames; the neck, which passes 






LOCOMOTIVE ENGINES. 233 

into the fire-box, contains fourteen T 3 g" wick-holders. 
This lamp is similar to the last, but the funnel — for 
pouring in spirits of wine — comes up at the back 
behind the buffer-beam, and is placed inside the 
right-hand buffer, passing as far up as the coping 
of the coal-bunker. 

The bogie-truck is similar to the last, except that 
instead of sheet-brass cross-pieces, the front, and 
back stays consist of copper wires riveted to, and 
passing between the side frames. The bogie-wheels 
are not solid, but have spokes. There is no link 
reversing-gear, but reversing is effected by loose 
eccentrics, one for each cylinder, similar to that 
described on page 134. 

The safety-valve is placed on the top of the dome, 
the crown of the dome being its seating. A boss 
must be cast on the dome, and drilled to receive 
the valve. A lug or fulcrum is screwed into the 
crown to take one end of the lever (pivoted to it). 
A spring-balance, attached by a pivoted joint to 
the top of the boiler, has its rod passing through 
the other end of the lever, and the lever is tightened 
on the valve by a nut. This valve does act, but is 



234 MODEL ENGINE CONSTRUCTION. 

more for appearance' sake. The direct-acting spring- 
valve in front of the cab is the one that relieves 
the boiler of excessive pressure, and must be 
so arranged by tightening the spring that it will 
blow off when the pressure rises above 30 lbs. per 
square inch, but not under that. The valve screws 
into a casing, soldered on the boiler, and through 
this we pour water into the boiler, after removing 
the valve for this purpose. There is no whistle, or 
brake applied, but we will describe one suitable for 
this locomotive. 

The boiler is made of copper, the dimensions being 
the same as that described on page 37, to which 
reference can be made. Cylinders are T y X 1", 
steam-ports yV" x f ", exhaust-port ■£%" X f". The 
barrel and outer fire-box is made from No. 24 
sheet copper, the internal fire-box, fire-tube, and 
tube-plate of No. 21 sheet copper; the frames are 
made of No. 20 sheet brass. 

Details for the construction of a link motion, if 
it be desired to fit one on, can be got by referring 
to pages 136, 139, and 171, but if the locomotive 
is fitted with loose eccentric reversing-gear, it will 



LOCOMOTIVE ENGINES. 235 

run more easily under steam than with, the link 
motion, as there is less friction set up. 

This engine has the regulator and cock arrange- 
ment for controlling steam to the cylinders similar 
to that in the previous locomotive (see pages 43 
and 212; also Sheets No. 1 and No. 11, B). 

The brake (see elevation, Sheet No. 12). Wooden 
blocks are screwed or pinned to hangers ; these are 
operated on by the horizontal rod, levers, and screwed 
rod in the brake pillar, which is fixed vertically upon 
the side of the foot-plate on the inner side of the 
water-tank. The rods on each side are single, and 
pass outside the driving-wheels; the hangers are 
made of stiff sheet brass, a flat piece being left pro- 
jecting from one side (see Sheet No. 12). This piece, 
when bent at right angles to the hanger with pliers 
or by hammering, forms the attachment for the 
brake-blocks. The hangers are soldered on each side 
to the ends of two stiff wires, which pass through 
them and revolve in bearings, or rather in holes, 
cut opposite each other in the frames. Collars are 
soldered on the wires bearing against the frames, 
which keep the hangers from shifting their position 



236 MODEL ENGINE CONSTRUCTION. 

(this method of attaching the hangers to the frames 
is the easiest in a small locomotive). The bottom 
ends of the hangers are pivoted by means of fine 
copper- wire rivets to sheet-brass horizontal rods. The 
brake weigh-shaft (of wire) is carried in sheet-brass 
hang-down bearings, soldered at one side inside the 
frame-plates. The lever on the brake weigh-shaft 
operates the horizontal rods, and is itself moved 
by the lever and a pivoted nut, as already described 
for the tender and traction engine. The brake 
pillar may be a casting. There is a globular expan- 
sion of the screw at its upper end, which is embraced 
between hemispherical recesses, one half in the 
top of the pillar, the other half in its cap, and 
in this way the brake-screw turns freely by the 
hand-wheel, but cannot lift, and so elevates or 
depresses the nut and the lever, according to which- 
ever way turned. The above should turn out a 
good working locomotive, and weigh fully in working 
order 6f lbs. 

Locomotive with single driving-wheels (see Sheet 
No. 13). This locomotive being without coupled 
wheels, side-rods, and bogie-truck, is the simplest 



LOCOMOTIVE ENGINES. 237 

form to make, and will ran the easiest of the lot. 
The boiler is constructed in the same way as those 
already described. The safety-valve, instead of being 
mounted on the dome, is fixed on a seating formed 
of a casting, or of sheet brass soldered together 
and placed over the fire-box. This is given for a 
variation, but the valve may be set on the dome 
as before. The side frames are cut so as to appear 
bent downwards in front of the smoke-box, for the 
purpose of keeping the buffers at the same height 
from the rails, as in the other locomotives ; but this 
is not necessary. There is no transverse plate pass- 
ing across below the cylinders for a bogie -truck to 
be supported under, but the frames are cut suitable 
for taking six wheels. The leading-wheel is small, 
in order to keep clear of the cylinder and piston- 
rod when revolving. There is only one guide-bar, 
an under one, for the piston-rod, the arrangement 
of the side-plates leaves no room for an upper one. 
The driving-wheels are placed in front of the fire- 
box, just far enough to allow the eccentric-sheaves 
and pulleys to clear the latter. The splashers are 
outside only, and the outer angles above the frames 



238 MODEL ENGINE CONSTRUCTION. 

are curved to clear the connecting-rod; the splashers 
are represented as having a sand-box, from which, 
in front of the driving-wheels, a pipe for sand is 
placed. It will be noticed that the distance between 
the driving- and trailing-wheels is out of proportion 
to what it would be in a real locomotive; this is 
done for the purpose of getting in a large fire-box, 
as with fire-boxes proportionate in every respect 
these small engines will not work, and we wish to 
describe here only what, when made, will give satis- 
faction as good working locomotives. The trailing- 
wheel is much larger than the leading- wheel ; this 
is in order to raise the axle above the lamp, so that 
it will not interfere with its being pushed in and 
drawn out. The shape of the cab is slightly different 
from what we had before. Of course the cab may 
be omitted, and only a wind-guard put up instead. 
The springs in front are "imitation ones," similar 
to those on the tender (see page 223). The 
connecting-rod is solid at both ends; either link 
motion or loose eccentric reversing-gear can be 
adopted. For dimensions, see Sheet No. 13. The 
sides of the cab and roof are soldered to the saddle- 



LOCOMOTIVE ENGINES. 239 

plate, and fixed at the foot on the top of the over- 
hanging frames by small bolts and nuts passing- 
through angles on the cab and frames. The lamp 
must have fourteen -f^" wick-holders. The barrel of 
the boiler and outer fire-box is made of No. 24 sheet 
copper. Internal fire-box, fire-tube, and tube-plate 
of No. 21 sheet copper, and frames of No. 20 sheet 
brass. The regulator and cock arrangement for 
admitting steam to the cylinders is the same as 
in the other locomotives. A tender suitable for 
this engine may be made from directions given on 
page 221, and from the drawings on Sheet No. 11, C. 
A larger and more powerful working locomotive 
can be made by doubling (so far as practicable) the 
dimensions over all of the locomotive on Sheet No. 
13. The boiler is made the same as described on page 
46, and exactly twice the size of working drawings 
on Sheet No. 1. It must be brazed at every joint, 
fitted with a ^' safety-valve, a small grate, and with 
the pump described on page 71. To get the boiler in 
between the frames and leave a little room for expan- 
sion, the latter should be set at a distance of 5-J" apart, 
but the thickness of metal required in them to give 






240 MODEL ENGINE CONSTBUCTION. 

rigidity, along with the axle-boxes, prevent us from 
gauging the rails at 5|", so we must gauge them 
at 6^-", and make other slight alterations here and 
there. The frames must be made of iron ^%" thick, 
cut to outline by drilling and filing, then attached 
by bolts and (cast) brass angles to the buffer-beam 
in front, and to the cross-stretcher behind. The 
cylinders are of iron, placed outside, 1" bore, 2" 
stroke; steam is admitted to them by a T V' cock 
and pipe ; blast-pipes \" bore. The wheels can be 
made of iron, -§■" thick, and T V' broad on the tread ; 
flange T V' nearly; axles, of iron, T 5 g" thick. The 
distance between the outsides of the overhanging 
frames is 9". 

A tender may be made by doubling the dimen- 
sions over all of that on Sheet No. 11, C, and 
altering where required, to make it suitable for 
this locomotive. The whole thing can be made by 
soldering together sheet brass, and fitting axle-boxes 
on the frames; the tank ought to be utilized to 
carry a supply of water to feed the boiler. 

A locomotive and tender such as this will run 
very well out of doors upon rails, aud pull a 



LOCOMOTIVE ENGINES. 241 

considerable load behind it. The engine can be 
fitted with reversing link motion or loose eccentric 
reversing-gear, as desired. All the turning required 
to make this locomotive can be done on the lathe, 
described on page 3, with the exception of the 
driving-wheels, which had best be turned by the 
brass finisher after they are cast. 

A six-wheel coupled tank locomotive is given on 
Sheet No. 14, such as is used for working branch- 
line trains and for shunting purposes. More friction 
is set up in this form of engine than in the others, 
from the coupling-rods being attached to six wheels. 
By adopting a short stroke and small driving- 
wheels, this locomotive will work fairly well, with 
twelve ■£$" wicks burning in the fire-box. The 
frames are 14" long, and are cut to suit six wheels 
of equal size, these being each 2^" diameter. The 
front wheels are much nearer the central pair 
than the trailers are ; this, as was explained before, 
is done in order to get a large fire-box in between 
the axles. The coupling-rod is jointed just behind 
the driving-wheel crank, for the purpose of dimin- 
ishing friction. The cylinders are set so as to be 

R 



242 MODEL ENGINE CONSTRUCTION. 






inclined at an angle to the driving-wheels. There 
is only one guide-bar for the piston-rod. The foot- 
plate is entirely covered in by the cab, there being a 
doorway on each side. The back saddle-plate is cut 
for two circular windows, the same as the front one. 
As it is absolutely necessary to get your hand into 
the regulator when running the engine, we have 
made the roof of the cab portable, so as to lift, 
off from the sides of the cab and coal-bunker 
(see drawings of roof in Sheet No. 14, and. dotted 
lines in the elevation). The hind saddle-plate, 
the roof, and the sides of the doorways simply 
rest upon the sides of the cab and coal-bunker, and 
can be lifted off when required. They are kept in 
position by strips of tin soldered on the inside which 
fit against the sides of the cab, which are perman- 
ently fixed to the foot-plate. In order $o clear the 
axle of the leading-wheels, the (wire) eccentric- 
rods should be bent into a semi-circular shape (see 
drawing), and pass below the axle. The boiler barrel 
and outer fire-box is made of No. 24 sheet copper, 
the internal fire-box, fire-tube, and tube-plate of 
No. 21 sheet copper, and the frames of No. 20 sheet 



LOCOMOTIVE ENGINES. 243 

brass. The engine can be fitted up to run in one 
direction only, or with reversing-gear, which may be 
either of the link motion or loose eccentric variety. 

We have taken up one or two different types of 
locomotive engines, for the purpose of giving the 
amateur a few selections to choose his " model " from 
that he intends constructing. The reason why we 
have given examples of tank engines is that these 
locomotives, not being burdened with an almost 
useless (at least to them) appendage, viz. the tender, 
have more power, and prove more satisfactory 
under steam, than those provided with a separate 
tender. 

We must bear in mind that, however well and 
carefully made a small locomotive is, it will never 
pull upon rails such a big load behind it as one 
would expect, at least to be at all in proportion 
to the amount of work done by a real locomotive 
upon the railway. This is owing to the fact, that 
in these small boilers, with all the heating surface 
you can obtain, steam of over 30 lbs. per square 
inch, or two atmospheres, cannot be generated and 
kept up. So that if one of these locomotives 



244 MODEL ENGINE CONSTRUCTION. 

runs well upon a level railway, both backwards and 
forwards, and can at the same time pull two of the 
coaches to be shortly described, it may be regarded 
as a first-rate working locomotive. 

It will be noticed that all the engines described in 
this book, as well as the locomotives, have a funnel 
or tube passing vertically upwards from the tank of 
the spirit-lamp just behind the fire-box, and through 
this tube spirits of wine is poured in as required, to 
keep the flames brisk when the engine is at work. 
This plan gives good results, and so we bring it 
before the notice of our readers. 

Directions for working the locomotives, which 
apply to stationary engines as well : — 

1. Oil the motion well, especially the eccentric- 
spindles, pulleys, piston-rods, coupling-rods, and 
axles. If oil can be put inside the valve-casing to 
oil the slide-valve, it is best to do so. Use a small 
oil-can, or dip a wire in the oil, and apply to the 
different parts. The oil used by watchmakers is 
perhaps the best for these small engines. 

2. Unscrew the safety-valve casing, or water- 
plug, and fill the boiler with cold, but preferably 






LOCOMOTIVE ENGINES. 245 

warm water, till it rises just to the top of the inner 
fire-box (as seen through the plug-hole) ; screw the 
plug or valve on again. 

3. Pour spirits of wine or methylated spirits 
through the funnel (that leads to the lamp) behind 
the foot-plate or coal-bunker, and fill the tank 
about half full. Be careful not to put in too 
much, as the spirit is apt to overflow and prove 
troublesome. Light the fire by a taper or match 
pushed through the fire-door aperture. Steam 
rises from cold water in about five to eight 
minutes. 

4. When steam is up, as indicated by its escape 
from the safety-valve (which must be properly set 
by tightening up the spring as required), pull the 
regulator outwards from the boiler, to admit steam 
to warm the cylinders. When it issues freely as dry 
steam from the blast-pipes, close the regulator by 
pushing it in towards the boiler, and wait till the 
steam gets strong (say about 30 lbs. per square 
inch) ; then place the reversing-lever in the first 
notch of the quadrant, or, if there be no link motion 
but only loose eccentric pulleys, push the engine by 



246 MODEL ENGINE CONSTRUCTION. 

hand forwards for a short distance to throw the 
eccentrics into forward gear. Then open the regu- 
lator, and the engine will run forwards. To stop, 
close the regulator. To reverse, shift the reversing- 
lever from the forward to the backward notch in 
the quadrant, or if there be no link motion but 
loose eccentrics, push the locomotive backwards a 
short distance to throw the eccentrics into backward 
gear, open the regulator, and the locomotive runs 
backwards. To stop, close the regulator. Stoke the 
fire, and keep it brisk during the time steam is 
up, by pouring in spirits to supply the wicks as 
required. One of these locomotives will run from 
fifteen to twenty minutes after steam is up, without 
any fear of the water getting short, and so melting 
the solder. The brazed fire-box allows of this, 
because though the crown is uncovered by water, 
there is no solder there to melt. 

5. When the run is over, draw the fire, by pulling 
out the lamp from under the coal-bunker, or if there 
be a tender, this latter must first be uncoupled from 
the engine to get the lamp out ; then blow out, or 
smother the flame with a cloth ; it cannot be readily 



LOCOMOTIVE ENGINES. 247 

put out while the lamp is in the fire-box. Next 
replace the lamp by sliding it along the groove 
under the coal-bunker or foot-plate, and couple on 
the tender, if there is one. The water can be left 
in the boiler, as copper does not rust, or it can be 
emptied out by unscrewing the water-plug, and 
turning the engine upside down while holding it 
in the hands. 

6. Occasionally the fire-tube and funnel should 
be cleaned, by passing a small round brush through 
them; the sides and crown of fire-box should also 
be scraped sometimes to remove soot (from the lamp- 
flames), which tends to gather to a small extent 
upon these parts. 

7. Place fresh wicks in the lamp-holders when 
required : these may be composed of either cotton 
or asbestos twine. There is an advantage in using 
the latter, for it does not burn away so rapidly 
as the former. 

8. When steam is noticed to leak through the 
eccentric and piston-rod stuffing-boxes, the glands 
must be unscrewed, the stuffing-boxes packed with 
fresh tow, wound round the rods, and the glands 



248 MODEL ENGINE CONSTRUCTION. 

screwed up again against the packing, to compress 
it and render the stuffing-boxes steam-tight. 



How to pack Locomotive Glands. 

Re-packing the locomotive glands with fresh pack- 
ing (which requires to be renewed now and again, 
if the engine is run often) is rather a difficult job, 
but may be done as follows. For the piston-rod, 
lay the locomotive upon its side on a table, place 
the piston on the back dead-centre, or with the 
rod fully drawn out, unscrew the gland from the 
stuffing-box, push it well forwards on the rod till 
it is close to the cross-head, to give you room to 
work : it is not necessary always to take out the 
old packing. Take a long piece of tow, about the 
thickness of a thread, grease this well by soaking 
it in melted tallow; holding one end of the tow 
in the left hand, with the right hand wind it 
lightly round the piston-rod, making two coils, 
or at most three. With a sharp pair of scissors 
cut the tow short, and with a fine knitting- or 
darning-needle push it well down into the stuffing- 



LOCOMOTIVE ENGINES. 249 

box, equally all round the rod, screw the gland 
firmly up against the packing, to tighten it, and 
then slacken back the gland a little to free the 
packing, oil the piston-rod, and the whole is com- 
plete. If the piston does not move easily, slacken 
the gland a little backwards with a pair of watch- 
maker's pliers. The slide-valve glands are packed 
in the same way; when doing them the loco- 
motive must be set on end, with the smoke-box 
downwards, or turned upside down, resting on 
wooden blocks. It is very important that the 
slide-valve glands be properly packed, or much 
steam will be wasted by blowing through them. 
A blow through one of these glands affects the 
engine more than when the pistod-rod glands leak. 
.As regards the piston, if it is properly fitted, 
and packed with tow soaked in tallow when the 
locomotive is made, it will keep tight for a long 
time, and the re-packing of it may practically be 
ignored. 

Note. — The locomotives with good strong steam 
can draw two coaches, but if steam is allowed to 
fall and become weak, none of them are able to 



250 MODEL ENGINE CONSTRUCTION. 

move themselves, or if at work, they will stop and 
cause disappointment, when the real cause of their 
stopping is no fault in construction, but merely 
a want of power in the steam to propel them along. 
Castings for making locomotives, with boiler 
materials, can be purchased from the model- 
maker's, and these vary in price from 10s. to 100s. 
and upwards, according to their semblance to a 
real locomotive. 



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CHAPTEE X. 

CARRIAGES AND RAILWAYS. 

Rolling stock (see Fig. 55 and Sheet No. 15). 
Here will be found working drawings of a correctly- 
designed three-compartment carriage, suitable for 
our railway. The carriage has only three compart- 
ments, which are quite sufficient for a model; 
having more simply means adding to the weight, 
and makes it more difficult to be pulled along. The 
frame is of wood, and consists of two longitudinal 
soles, or side timbers, extending from end to end, 
between the end timbers. These are narrower along 
the greater part of their length than at the ends, 
here they are |" in depth. This is done to lower 
the buffer-beams, and keep the buffers on a level 
with those of the locomotive. The end timbers join 



254 MODEL ENGINE CONSTRUCTION. 

the longitudinal ones at the ends, and are fastened 
to them by glue and small sprigs (for dimensions 
see drawings). The brass buffers are screwed into 
the end pieces, as well as draw-hooks, similar to 
those already described. Cross or diagonal pieces 
of wood need not be put in between the frames 
to stiffen them, as the end pieces do all that is 
required. The wheels are put inside the longi- 
tudinal timbers, which are placed at a distance 
of 3j" over all. The bearings are made of sheet 
brass, the axles revolve in holes drilled through 
them : they are cut to outline. Axle-boxes and 
imitation springs, similar to those on the > tender, 
can be put on if desired ; or the bearings may 
be carried up, and screwed simply to the sides of 
the longitudinal timbers ; but as these are too thin 
to stand a wood screw, it is best to put a small 
screw through, two for each bearing, with a nut 
which can be tightened up on the inside and 
hold them firmly. The wheels are of brass, 1-f-" 
diameter, turned on the lathe, and firmly fastened 
to their axles, which pass through them before they 
enter the bearings, the same as in the tender. The 



CARRIAGES AND RAILWAYS. 255 

axles are straight, and of the same thickness 
throughout. The wheels are kept from striking 
against the bearings when revolving by having 
projecting bosses, or narrow brass rings inserted 
between them and the bearings. These rings are 
slipped over the axles before putting them in place. 
A foot-board is made of thin wood, -|" thick, 
and T V' broad, one on each side. Each is 
fastened to the frames thus : Cut a long strip 
of sheet brass (there must be three supports, one 
near each end, and one at the centre, each T \" 
broad), and bend into shape shown ; all the strips 
must be cut to the same size. Drill a hole in each 
support through both projecting crank-ends, and 
fasten the foot-board to these, by one little bolt 
and nut for each. Fasten the sheet-brass strips 
transversely under the carriage frames by bolts, 
one on each side, and the foot-board is complete, 
after a stiff wire (bent to the same shape) has been 
soldered underneath the brass supports (below the 
foot-plate) as well as under the body of the carriage. 
This wire stiffens the supports, and prevents the 
foot-board from being bent in any way. A piece 



256 MODEL ENGINE CONSTRUCTION. 

must be cut out of the foot-boards, opposite the 
axle-boxes, upon the inner sides. 

The body of the carriage is best made of wood ; 
tin-plate might do, but the first is preferable. The 
body is fastened to the frame by glue and sprigs 
(drilling holes in the wood first of all, as it might 
split unless this is done), which pass through the 
floor. The body must be attached to the frames 
before putting on the roof. The ends are quite flat, 
but arched at the top to suit the curvature of the 
roof. The carriage sides are both exactly the same, 
so that a description of one applies to the other. It 
is made of wood, \" thick ; the windows and door- 
ways must be carefully marked out and measured, 
while the piece of wood lies upon a flat surface, then 
gouge out the windows, cut, and file to outline. The 
doorways had best be cut in the same way, as with 
such thin wood a saw might split it, but by gouging 
out the pieces, while the wood lies on a flat surface, 
this will not readily happen. The windows are six 
in number, 1" x \". The doorways are rather larger, 
and must be prolonged downwards till they meet 
the lower free ends. After this, nail the sides to 



CARRIAGES AND RAILWAYS. 257 

the ends, and for this purpose use fine sprigs and 
glue. The two cross-pieces or divisions of the com- 
partments are made the same as the ends, and 
fastened in their respective places. Fasten on the 
floor-piece, and nail a piece of wood right across 
upon each side of the doorways for seats, in all 
the compartments. For the roof, procure a piece 
of wood of the size given in drawing, plane it 
quite flat, and in order to bend it round to the 
correct curvature of the ends of the carriage, with 
a fine saw make a number of parallel longitudinal 
saw-cuts from end to end, going fully three-quarters 
through the wood — make all the saw-cuts on what 
is to form the inside of the roof — boil the piece of 
wood, and steam it well for two or three hours, 
and having planed the upper edges of the sides 
level, bend 4he wood over the ends of the carriage 
(which it will easily do while still warm), keeping 
the saw-cuts on the inside, and running in a longi- 
tudinal direction. The roof must now be nailed to 
the ends, sides, and divisions of the body. Drill 
holes through it, coat the under surface near the 

edge with glue, and nail with fine sprigs to the body 

s 



258 MODEL ENGINE CONSTRUCTION 

of the carriage. Lay aside to dry, and afterwards 
plane the edges flush with the ends and sides of 
the carriage, or let them project over the latter 
a very little. Turn a piece of wood on the lathe, 
1 j-" long, to a -|" diameter, cut this into three pieces, 
each i" long ; drill a hole through the centre of the 
roof of each compartment — this hole must be ver- 
tical — it need not go through, but should be nearly 
y in diameter ; there are three holes in all. Glue 
one of the pieces of wood into each hole, this 
gives a finish to the carriage, and looks like one 
of the ordinary lamp-covers that are fixed on the 
top of a railway carriage. 

The doors are six in number, made an easy fit in 
the doorways, each about \" thick ; a window must 
be cut out in the upper half of each. These doors 
may simply be made a tight fit in the doorways, or 
hinged by means of cloth and glue, attached on the 
outside, all down one side (the same as some of the 
small parcel-post boxes are hinged), or tiny hinges 
could be made of sheet brass and wire, these being 
fastened outside by small bolts and nuts to the 
carriage side of the doorway by one half, and by the 



CARRIAGES AND RAILWAYS. 259 

other half to the door itself. Glue on wooden pegs 
for handles, or turn half-a-dozen brass handles out 
of a piece of wire, cut them apart, drill, and tap 
with a thread, pass one through each of the doors, 
and fasten inside with a small nut. Any kind of 
proper fastening for attaching or locking the doors 
would be troublesome to fit up ; but if the doors 
are made a good fit in the doorways, they will 
remain tight when closed. 

We must now begin glazing operations, to com- 
plete our carriage. If the amateur does not possess 
a diamond for cutting glass, let him give the sizes to 
a joiner or a glazier, who will cut them for him. 
Being so small, the pieces will be troublesome to 
cut, but can be done with a little patience. If 
the tiny panes be tightly fitted in the windows 
and doors, they will remain fixed without anything 
more being done to them. Be careful in fitting 
not to split the doors or the carriage sides when 
putting in the glass, and this need not happen if 
due care be exercised. The fitting of the window- 
panes may be omitted, but if done, adds to the 
appearance of the model. These windows cannot 



260 MODEL ENGINE CONSTRUCTION. 

be raised up and down, as in an ordinary railway 
carriage, for this carriage is of too small a size to 
admit of window-frames being put in. 

The coupling-hook is fastened to the end cross- 
bars, as in the locomotives, and attachment can be 
made from it by three small links of brass wire, each 
about -§-" long, of oval shape, and made by bending 
a pin, cutting off the point and head, bringing to- 
gether the ends, and soldering the junction where 
they come together ; three links are sufficient. 
There is no coupling-screw, as this would be difficult 
to make with a right- and left-handed screw, such 
as it would require to have. 

The carriage has panelling on the sides. This is 
done by glueing thin strips of wood on the outside, 
underneath the windows, and around doorways 
and doors, after the carriage is put together, and 
before it is painted. This renders the carriage 
complete, but is difficult to do, and may be 
omitted ; in which case the carriage can be painted 
all of one colour, or the panelling can be repre- 
sented by gold, white, or black lines, according to 
taste. The weight of this carriage when finished 



CABBIAGES AND RAILWAYS. 261 

will be fully 1^ lbs. By means of bent wires 
pushed through the sides and ends, and fixed by 
nuts inside, hand-rails can be fitted up in different 
places ; even steps can be attached to the frames 
and ends of the carriage (these last are for the 
porters to get on to the roof to light the lamps, 
etc.). Steps are made by cutting out small pieces 
of sheet brass, J" X T V' > bend each at the centre 
into a right anode. One half is fixed to the end 
of the carriage by bolts, the other half sticks out 
and forms a step. 

Luggage van (see Sheet No. 16). It is con- 
structed after the same manner as the carriage. 
The longitudinal and cross frames, the floor, body, 
and roof, are put together in the same way. 
Towards one end of the van, it will be noticed 
that the roof is raised for a distance of If", about 
T V' higher than the remaining portion. This eleva- 
tion is formed of a solid piece of wood, cut concave 
below (to fit the roof) and convex on its upper 
surface ; this piece is glued or nailed on to the roof. 
The doorway is wide, and the door is made in 
two halves, upon each side, and is hinged on both 



262 MOVEL ENGINE CONSTRUCTION. 

sides by small hinges, or by cloth and glue. Both 
doors open outwardly. Place a small window in one 
of the ends of the van, the same size, and put 
at the same height as those in the doors. The 
wheels are If" diameter, fixed to their axles and 
bearings, as in the previous vehicle. Foot-boards 
are attached in the same way, as well as axle- 
boxes and springs. 

The brake, with its levers, rods, and blocks, is 
fitted up in the same way as that described for 
the tender. We have departed here in great 
measure from actual practice, and have carried up 
the brake-rod and hand- wheel or lever, and placed 
the latter on the top of the roof, as it is impossible 
to get the hand inside the doorway of the van to 
turn the brake off and on. The brake-pillar is a 
piece of sheet brass, screwed at the under surface to 
the floor of the van near one end, and the top is 
firmly screwed to the roof; the rod simply passes 
through two holes drilled in the frame, and is 
kept from rising and falling by a collar soldered 
on underneath the upper and under support, and 
above the frame by the boss of the hand-wheel, 



CARRIAGES AND RAILWAYS. 263 

which is firmly screwed to the rod ; the brake-pillar 
passes up inside the buffers, between them and the 
draw-hook. Panes of glass must be put in the 
doors and windows, and a piece of wood inserted in 
the roof to represent the lamp-cover. The wood 
of old cigar-boxes does very well to make the 
body of each carriage from, as this wood is about 
the correct thickness, is strong, and will stand 
nailing together with sprigs; if holes have been 
previously drilled for the sprigs to enter, the wood 
will not split. 

A truck or wagon (see Sheet No. 16) is very 
easily constructed, and is the last vehicle that we 
intend taking up. The buffers are simply the pro- 
jecting ends of the side timbers, the cross-pieces 
for the ends being between them. The floor is 
nailed on to the frames. The body can be made 
of separate pieces of wood joined together, or the 
sides and ends may be composed each of whole 
pieces, nailed together at the angles. The ends 
are curved upwards, and are highest at the middle. 
The wheels are 11" diameter, and revolve in sheet- 
brass bearings, which are fixed by angles and small 



264 MODEL ENGINE CONSTRUCTION. 

bolts to the under surface of the side timbers. 
There are no springs or axle-boxes. 

Any other size of wheels, slightly larger or 
smaller than those given, will do for the carriages 
to run upon. If slight alterations are made in 
the bearings to correspond to the size of wheel 
adopted, and yet not raise the roofs any higher 
than the sizes here given, it would make the 
carriages seem rather out of proportion. 

A drawing of the train will be found in Fig. 55, 
which is composed of a bogie-tank locomotive, a 
passenger coach, and a guard's van. 

The railway. Two different kinds of railways 
suitable for the locomotives to run upon will be 
described ; the gauge of each is 2|". The first form 
is easily and cheaply constructed, being made of 
iron wire, soldered to strips of tin, fixed upon cross- 
sleepers, nailed to a board. The second form is a 
correct model, having cast-iron rails, secured by 
wooden wedges in brass chairs, spiked to sleepers, 
as on the railway. 

To make the first, procure iron wire of fully T V' 
thick (brass wire is not so good, as it produces more 



CARRIAGES AND RAILWAYS. 265 

friction when the wheels are running over it), cut 
the wire into lengths, each about 40" long, carefully 
straighten it by hammering with a light hammer 
over a flat piece of iron, or upon the vice ; cut 
strips of tin, 4f" long and 1" broad, nail these with 
a sprig near their ends to wooden cross-sleepers of 
about the same size, and -J" thick ; fix these sleepers 
at a distance of 3" apart from each other, in order 
to render the wire rails perfectly rigid. This 
allows about twelve sleepers to each section of line. 
Solder the wire down to the sleepers on the out- 
side, upon one side, and at a distance of 2|" solder 
down the wire on the other side. The solder, it will 
be seen, takes the place of chairs, and holds the 
rails in position. The length of line, viz. 40", is 
now complete. Any number of these sections can 
be made in the same way, and then the sleepers 
with the rails attached must be nailed down to a 
board, or a piece of flooring plank; the ends of 
one section of rail coming close up to those of 
the next section, so as to render the rails of the 
various sections all continuous with each other. 
Raise the board along with the rails upon wooden 



286 MODEL ENGINE CONSTRUCTION. 

supports, fixed at a height of say about 40" from the 
ground, and be careful that the line is fixed up 
level. Ascertain this by means of a spirit-level, 
after which the line is complete. It may be per- 
manently laid down in any outhouse or workshop 
(as these locomotives do not steam well outside, 
unless the day is very calm), and is ready for use at 
any time. If this line is properly made, it will give 
satisfaction, and there is little fear of the vehicles 
leaving the rails, if the flanges are good, and the 
gauge correct; but care must be taken that the 
flanges of the wheels (when running) keep clear of 
the tin sleepers, or otherwise considerable friction 
will result, and may cause disappointment, as the 
engine fails to start, or stops very soon after being 
set in motion. A curved line produces more friction 
than a straight one. A siding, points, and a crossing- 
may be easily made, by following the directions 
given under the second form of railway. The 
pointed end of the wire switches must be filed 
down very thin, where they come in contact with 
the stock rails. The two tongues of the points, 
in this case, should be soldered down to a strip 



CARRIAGES AND RAILWAYS. 267 

of tin, which passes under the main-line rails, and 
rests upon a wooden sleeper, but is not attached 
to it. To the end of this tin plate, on one side, 
a wire is fastened which pivots to a lever in the 
ordinary way. Pulling or pushing this lever causes 
the points to be set for the siding or main line, as 
desired. The tin plate, with the points attached, 
will not move freely on the wooden sleeper below 
it, unless the plates attached to the second and 
third sleepers from the points slide also upon their 
respective sleepers. In this way the heel of the 
points can be soldered to the cross-plate, and no 
pivots are required. The crossing is made in the 
same way as that to be described further on, there 
being both wing and guard-rails made of wire. The 
rails must be bent away from the main line, and 
fixed to the sleepers with solder. Gaps must also 
be made, to allow the flanges of the wheels to 
pass. 

The second form of railway (see Figs. 56 and 
57 — which are full size — and Sheet No. 17). A 
pattern for a rail and chair must first be made in 
wood (see pages 305 and 306), and castings obtained 



268 



MODEL ENGINE CONSTRUCTION. 



from them. Get the rails cast in malleable iron, 
as these castings are soft and easily manipulated. 
Each rail can be bent into a circular shape, or 



B 




D D <Q □ 



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Fig. 56. — Railway. 

A, wooden sleeper ; B, rail ; C, chair with wooden wedge ; 
D, fish-plate. 

hammered, without fear of it breaking, as an ordinary 
cast-iron rail would do. The rails, after being 
straightened by hammering on a flat surface, should 




Fig. 57. 



be filed over on the head, heel, and sides, then 
polished upon the upper and inner surfaces, by 
rubbing on the grindstone, and finished with coarse 



CARRIAGES AND RAILWAYS. 269 

and fine emery paper and oil, then they will 
become as smooth as glass, and reduce friction to 
a mimimum, when the wheels pass over them. Get 
all the chairs cast in brass, file them flat on their 
under surface, and each must be drilled near the 
ends for two bolts, to spike them to the sleepers. 
To save expense, four chairs, or even three, might 
do for each rail. The sleepers should be 4-f-" long, 
IV' broad, and about J" thick, and these, instead of 
being embedded in ballast, should be nailed to a 
board, raised about 40" from the ground, as before. 
Care must be taken that the inner jaws of the 
chairs do not project so far up against the web of 
the rail as to rub on the flanges of the wheels when 
passing over them. When fixing the chairs and 
the rails upon the sleepers, a measuring instrument 
or gauge should be used to see that the rails are 
set at the proper distance apart. This can be made 
out of sheet brass, having a piece cut out of it 
at each end, and leaving a prong, or wider piece 
between the rails. The ends of the gauge lie on the 
upper surface of the rails, and the distance between 
the outside edges of the upper part of the prongs 



270 MODEL ENGINE CONSTRUCTION 

is the gauge of the railway. A rigid connection 
of the rails endways can be made by fixing the 
ends of each rail into a joint chair, half of the 
chair going to one rail, and half to the other; or 
if we want a correct model, by joining the ends of 
the rails by fish-plates (see drawings), made of stiff 
sheet brass, each 1" x ■£%" nearly, one being placed 
on each side of the web of the rail. The upper and 
lower edges of the plates are filed at an angle, to 
fit accurately the sloping sides of the head and foot 
of the rail. Bolts (either two, as on the railway, 
or one) should pass through the rail and the two 
fish-plates, and draw the plates together. Then 
tighten them up against the rail with nuts. Of 
course this necessitates very accurate drilling of all 
the holes in the rails and fish-plates, so that the 
bolt-holes may correspond. The bolt-head is placed 
on the inside, and the nut outside. A distance of 
from fifteen to twenty feet would be a fair length 
to make the line, a less distance than this is rather 
too short for a good run. 

A siding can easily be made with the malleable 
rails (as they bend easily), running off from the 



CARRIAGES AND RAILWAYS. 271 

main line. If properly gauged, and the curve 
correctly set out, the model will work well, and it 
is interesting to see an engine take the points and 
run round the curve under steam, dragging a coach 
along with it. A curve with a radius of ten feet 
will allow any of the locomotives and carnages 
mentioned above to pass round it, but the outside 
rail must be slightly elevated above the inside rail, 
with a gradual rise from the main line to the 
sharpest part of the curve. Points are movable 
rails, by means of which the direction in which 
a coach is travelling is changed, and crossings are 
gaps in the rails through which the flanges of the 
wheels pass when a coach on one line crosses to 
another line. Two drawings of a pair of points are 
given: in Sheet No. 17 the points are standing 
right for the main line, and also for a line diverging 
to the left. The wheels of the coaches are kept 
on the rails by the flanges on the inner sides, so 
the wheels follow the guidance of the rails, and 
the path they travel in each case is shown by the 
shaded lines. The points are ordinary rails, which 
must be filed down very thin at one end, and 



272 MODEL ENGINE CONSTRUCTION. 

pivoted by the other. The pivot end is called the 
heel of the points, and must be so placed as to allow 
room for the flanges to pass easily between it and 
the stock rail. When a pair of wheels has been 
guided on to the diverging line, and continues to 
travel on this line, the flanges of the right-hand 
wheels will have to cross the rails on the near side 
of the straight line. This is done by making a gap 
in the straight rail, and to allow the wheels on 
the straight line to cross the diverging line, a gap 
is required to be made in the diagonal rails. The 
intersection of the rails at the gaps constitutes 
a crossing (see plan, Sheet No. 17). In order that 
the flanges of the wheels may pass through the 
gaps, the wheels -near the crossing, and the opposite 
wheels, are guided by wing rails and guard rails, 
fixed near to and opposite the gaps, and these, 
acting as check rails, prevent the wheels from 
diverging to the right or left, and so pass through 
the gaps in the wrong direction. The crossing can 
be made from the main line at any angle so long 
as the gaps can be properly protected with guard 
and wing rails. In making a siding, the ends of 



CARRIAGES AND RAILWAYS. 273 

the points must be filed down very thin, the ex- 
treme end made so as to be kept lower than the 
top of the stock rail, and below the level of the 
flanges of the wheels, and the pointed end must 
fit very accurately against the stock rail. The two 
tongues of the points must be rigidly connected, 
so that they may move accurately together, and 
that the horizontal distance between them may be 
properly preserved. Make the connection between 
them by means of a piece of brass wire, having collars 
on the inside for the rails to rest against. The free 
ends of the wire which pass through the rails can be 
riveted firmly on the outside of the web of each rail. 
To move the points, one of the connecting-rods 
is prolonged on one side, or a separate rod is used, 
cranked beneath the rails, and rising, so that it may 
be fastened to the point rail, or centre of the 
connecting wire. This rod is extended horizontally, 
and pivoted to a lever, which itself pivots in a 
bearing fastened at a proper distance from the line, 
to be clear of the trains when passing. This lever 
must be moved, when it is desired to alter the 
position of the points, or it could be fixed by a 

T 



274 MODEL ENGINE CONSTRUCTION. 

spring, so as to keep the points set for the main 
line, and only require moving when it is desired to 
run to or from the siding. At the crossings, the 
rails require to be filed away, so as to meet at the 
correct angle with each other, and be firmly wedged 
down to the chairs as well. The siding can be 
prolonged for any convenient length. 

A simpler plan of arranging the points, and one 
that will save some fitting, is to adopt the original 
mode of providing for trains crossing from one line 
to another, and which is still used by contractors 
on their temporary railways. In this method (see 
Sheet No. 17) the four ordinary rails of the two 
diverging lines are brought as near together as space 
required for the flanges of the wheels to pass 
permits ; and the two rails of the single line are left 
of the ordinary size, and are pivoted, so' that their 
free ends can be placed opposite the ends of either 
pair of the diverging lines as required. The move- 
ment of these can be regulated by a lever as before, 
and the movable rails are kept fast together by a 
bar that passes between them. If the railway is 
made a straight one, it will give the best results, 









CARRIAGES AND RAILWAYS. 275 

as a circular line always causes considerable friction, 
and prevents the trains from running so easily 
upon it. The same remark applies to wooden rail- 
ways, whether circular or straight. Another plan of 
fixing the rails to the sleepers, which does quite 
as well, and saves getting brass chairs cast, is to 
set the rails direct upon cross-sleepers, nailed to a 
board at a distance each of 3" apart, omit chairs, 
and use what practically amounts to chairs. This 
consists in forming each chair of two separate pieces 
of hard wood, each about j" long and J' thick 
(preferably from the wood of a cigar-box). Nail one 
piece outside the rail on a sleeper, and the other 
inside the rail opposite to it. The edge of each 
piece of wood should be made convex towards 
the rail, so as to pass inside the groove, and grip 
the web tightly upon each side when nailed down, 
and so hold the rail firmly — only the wood must 
be cut away on the inside, so as not to rub against 
the flanges of the wheels when passing over the 
wooden chairs. The rails may be attached to every 
second sleeper, which is quite sufficient, whether 
fish-plates are used or not. Make sure that the 



276 MODEL ENGINE CONSTRUCTION. 

rails are properly gauged before nailing (with -|" 
sprigs) the two pieces of the chair down to the 
sleepers, or there is trouble afterwards to get the 
rails back to the proper gauge. Our reason for 
adopting cross-sleepers under the rails, and not 
fastening the latter direct to the wooden board, is 
in order to allow access of plenty of air to the loco- 
motive fire-boxes, to support combustion. 

If brass chairs are adopted to fix the rails (when 
laying them) wooden wedges must be cut, each 
about ■§■" long, and driven firmly in between the 
rail and chairs on the outside. It is best, and 
perhaps easiest, in order to gauge the rails properly, 
to wedge them to the sleepers first, and then, when 
fixed, bolt the chairs and the contained rail to the 
sleepers ; lay down one rail first, and then lay down 
the opposite rail at a fixed distance from it, using the 
gauge to get the correct distance. It will be seen 
that a few sleepers are cast of a different form for the 
points and crossings, and patterns for these must be 
made specially. 

If the line is laid down permanently in a work- 
shop or outhouse, where there is the slightest damp- 



CARRIAGES AND RAILWAYS. 277 

ness, the surfaces of the rails are apt to become 
tarnished over, or it may be coated with rust, which 
spoils their efficiency, and in order to keep them in 
good working order their upper surfaces should now 
and again be rubbed over with fine emery cloth, and 
smeared with a little oil. 

Railway signal (see Sheet No. 18). We adopt 
the ordinary semaphore signal. The post is made of 
wood, dove-tailed, or otherwise fixed in the wooden 
board upon which the line is carried, and set near 
the junction (the correct distance is out of the 
question, as the line is too short to admit of this). 
The upper end of the post has a longitudinal slot 
cut out, through which the sheet-brass arm passes, 
after being pivoted inside. When the arm is fixed 
horizontally, this indicates danger, and when it falls 
nearly vertical it shows the line is clear. A small 
crank is soldered to one end of the wire that passes 
through the upper part of the signal-post; this 
wire has the signal-arm fixed upon it, and oscillates, 
in response to the movements of the crank, in a 
horizontal hole drilled through near the top of 
the post. The arm can be fixed inside the slot, or 



278 MODEL ENGINE CONSTRUCTION. 

outside upon one side of the post ; it is all the 
same, as both forms are used on the railway : the 
last is perhaps the easiest to fix up. A sheet- 
brass rod, or a wire, connects the crank to one arm 
of a weighted lever, pivoted near the foot of the 
post, while the extremity of the short end of this 
lever is attached to a small chain, which passes 
under a pulley-wheel, and along the side of the line, 
to be connected with a hand-lever (working in a 
racket) at any distance chosen from the post. 

Make the arm of sheet brass ; if placed outside 
the post, np slot is required. Drill a horizontal hole 
through the top of the post, attach the arm by 
solder to a wire, pass one end of this wire through 
the post, leaving the arm outside, put a nut on 
the end of the wire to prevent its being drawn 
out, and solder on a brass crank upon the other 
end for making attachment by to the levers. A 
nut fixed on the end of the crank-pin will prevent 
the long rod, going to the weighted lever, from 
coming off. If the arm is put inside the post, 
there is more difficulty in getting it fixed in- 
side the slot. The best way to accomplish this is 



CARRIAGES AND RAILWAYS. 279 

to make a saw-cut, from one side, right into the 
slot, to meet the upper and lower borders ; take 
the piece of wood out, drill a horizontal hole, from 
each side, into the slot, put through the wire as 
before, solder the arm to it, and fit a piece of wood 
into the slot on the opposite side, and drill a hole 
through it for the arm to pivot in, then fix on 
an outside crank. After painting, and attachment 
has been made to the levers, the whole is complete. 

A small chain," and any size of pulley, will do. 
The chain (it will be seen), when in the racket, 
passes underneath and upwards for a short distance 
behind the lever, and is attached to a snug on 
the back or farthest-away side of the lever from 
the signal. Both the racket and the lever may be 
made of brass, and set at any convenient distance 
from the signal. 

A suitable railway for the large locomotive de- 
scribed on page 239 can be made in much the same 
way as the above, but with heavier rails, chairs, 
and sleepers. The latter will require to be each 
about 10" long, and the former (if the line is per- 
manently laid down out of doors in a garden) had 



280 MODEL ENGINE CONSTRUCTION. 

best be made of brass; because small iron rails, if 
exposed to weather, will soon get rusted over and 
rendered useless. The brass rails will no doubt 
become tarnished, but this can soon be put right 
by fastening a piece of sandpaper to a piece of 
wood, and going over them now and again. The 
line could be raised on supports, but perhaps had 
best be fixed on the ground. Gauge of line is 6 J". 



CHAPTER XI. 

COMPOUND MARINE ENGINES. 

Compound non-condensing marine engine. This 
engine differs from all those hitherto described, 
in being of the compound type. By this we mean 
an engine in which the steam, after having done a 
certain amount of work in a high-pressure cylinder, 
exhausts from it into a larger low-pressure cylinder, 
where it does further work, and from this last, 
in our engine, it exhausts direct into the atmo- 
sphere. In a real engine of the condensing type, 
the steam, after passing out of the low-pressure 
cylinder, goes into the condenser, where it is con- 
densed into water. We have entirely omitted the 
condenser, with its circulating and air-pumps, from 
this engine, as being too complicated, and possibly 
might not work well when made on such a small 



282 MODEL ENGINE CONSTRUCTION. 

scale. This engine is of the cross cylinder type (see 
Sheet No. 19). The cylinders are placed side by 
side, and each connects with its own crank. The 
two cranks are set at right angles with each other, 
and this being so, when the steam is discharged from 
the high-pressure cylinder, at the end of the stroke, 
it exhausts into the receiver B, which surrounds 
the high-pressure cylinder, then it passes by the 
pipe C to the low-pressure cylinder, and is admitted 
to it by the slide-valve. From the low-pressure 
cylinder, as mentioned above, it passes out into 
the atmosphere through the exhaust-pipe D. It 
must be understood that the letters H.P.C. stand for 
high-pressure cylinder, and L.P.C. for low-pressure 
cylinder, and these letters will now be used when 
referring to these cylinders. 

Cylinders. The H.P.C. is £" bore, and the L.P.C. 
1-J-" bore, each with a stroke of 1". Both are made 
of brass ; the flanges of the H.P.C. are of the same 
diameter and thickness as those of the L.P.C, so 
that the top covers of both cylinders can be cast 
from the same pattern. By referring to Sheet No. 
19, it will be noticed that a considerable space (B) 



COMPOUND M AMINE ENGINES. 283 

exists round the body of the H.P.C. and the edges 
of the flanges ; this space is to be completely closed 
in, by means of a circular piece of sheet brass, 
extending above downwards from the edge of one 
flange to the edge of the other, and laterally from 
the steam-chest on one side (including the exhaust- 
pipe in its interior) passing round the cylinder, and 
is fastened to the opposite side of the steam-chest. 
This metal sheet is to be fastened to both cylinder 
flanges (all round) by means of small cheese-headed 
screws, screwed here and there into the flanges. 
And besides this, the edges of the flanges, the steam- 
chest, and the inside of the metal sheet (having 
been previously tinned) are to be soldered together 
above and below, and also to the sides of the 
steam-chest, so as to be made perfectly steam-tight. 
This space forms a jacket surrounding the H.P.C., 
and is the receiver, and here the exhaust steam, 
after coming out of the H.P.C, waits till the L.P.C. 
is ready to receive it. There is no outlet for the 
steam, except through the pipe C that is soldered 
into the receiver opposite the steam-chest, and 
which communicates directly with the L.P.C. steam- 



284 MODEL ENGINE CONSTBUCTION. 

chest. A cock should be screwed into the receiver, 
to let out any condensed water. These cylinders 
are rather small to have blow-off cocks, but if a 
lubricator, with a cock, is screwed through the 
top cover of each, this will do both for oil and for 
blowing out any water that may condense inside. 
These lubricators had best be purchased ready-made. 
Steam coming from the boiler is admitted to the 
H.P.C. by a cock, or wheel- valve, screwed into the 
valve-casing. Both cylinders are bolted by four 
bolts to the front covers. When fitting, centre 
the cover on the upper surface, punch a hole here, 
to correspond with the centre of the cylinder bore 
when bolted to it, drill this hole vertically down- 
wards for the piston-rod to pass through, now turn 
the standards upside down, and enlarge this hole 
for about half its depth from the under surface, 
and fit a stuffing-box gland to hold the packing. 

Both standards are fitted up in the same way, and 
must be filed smooth, and bolted, by means of the 
flanges (cast on their free ends), to the bed-plate. 
The piston, covers, slide-valves, and cases, must be 
fitted up as already described. The pistons are 



COMPOUND MARINE ENGINES. 285 

grooved, and packed with tow ; there are no piston- 
rings. The bearings for the crank-shaft are three in 
number, made of brass, and bolted to the bed-plate. 

The crank-shaft can be purchased from one of the 
model-makers, and finished on the lathe ; it should 
be \" thick, and T %" at the journals. A built-up 
crank-shaft can be easily made by filing up two 
blocks of brass to the sizes 1" x \" X Jj-" (see draw- 
ings, Sheet No. 19), drilling a fV' n °l e transversely 
through both, near one end, tapping with a thread 
for a yV" screw, and screwing in the separate pieces 
of the shaft. Before doing all this, slot out a 
longitudinal groove in each block (see drawings), 
so as to leave a thick piece of metal on each side, 
which forms the webs of the crank. The thick 
piece at one end is to form the crank-pin. Measure 
on the outside of each web a distance of J" from 
the crank-shaft centre, mark and punch a hole 
here : this forms the centre for the crank-pin. 
The crank-pin end of each block must be rounded 
and made narrower than the other end, then file 
out the crank-pin, and see that it is made to 
coincide with centres already marked. If the 



286 MODEL ENGINE CONSTRUCTION. 

pins be filed circular, the engine will work all 
right, without the necessity of their being turned 
on the lathe. The shoulders of each piece of 
the axle may be soldered to the webs, as well 
as screwed in, and this will make the axle quite 
strong enough. In this last case, where we em- 
ploy a built-up crank, there will be. no difficulty 
experienced in getting the eccentric-pulleys of 
the L.P.C slipped on to the shaft, as this can be 
done before the parts are permanently fastened 
together. When the shaft is a forging, it will 
be impossible to get the eccentric-pulleys over it, 
unless they are each put on in two halves. A 
rather troublesome undertaking with such small 
eccentrics; but it may be done as follows (see 
drawing). This method applies to both eccentric- 
pulleys. After finishing the pulley on the lathe, 
and drilling the centre of eccentricity, make a file 
mark across the pulley on both sides, in such a 
direction that the hole for the crank-shaft is halved 
in two by the file mark. From the bottom of the 
groove around the circumference of the pulley, drill 
a vertical hole that will pass right through the true 






COMPOUND MARINE ENGINES. 287 

centre of the pulley, and be at right angles to 
the file mark; drill this hole a good way deeper 
down than the centre of the pulley. With a small 
saw cut the eccentric in two halves along the file 
mark, widen the hole in one half of the pulley, 
for about half its depth — the head of the bolt, after 
being countersunk in the eccentric groove, rests 
in this wide part — tap the lower half of pulley 
with a small screw-thread, make a screw with a 
long head, so that the neck will rest against the 
narrow part of the hole in the upper half, and 
having slipped each half of pulley over the shaft, 
screw them together. Then file the head of the 
screw flush with the bottom of the eccentric groove, 
and the whole is complete. The eccentric-strap 
and screw will keep the two halves in line. These 
pulleys, being in two halves, had best be soldered to 
the crank-shaft, after finding their correct positions 
(see Chap. IV.), as a key might tend, when driven 
in firmly, to break the screw, and separate the 
two halves from each other. 

The valve motion requires little to be said about 
it, as all is rendered plain from the drawings. The 



288 MODEL ENGINE CONSTRUCTION. 

slot-links and lifting-links can be made out of soft 
iron by drilling, filing, and cutting to outline. A 
bearing is screwed to each standard, to support the 
weigh-bar. There are two double lifting-links to 
each slot-link, but a single one would be simpler 
to fit up, and do well enough. By referring to page 
139, you will find how to fit up the link motion. 
It will be a good plan, after finishing, to lag the 
cylinders with small strips of wood, -£§" broad, the 
lagging extending from the valve-casing of the 
H.P.C., over the outside of the receiver, to the 
L.P.C., passing round it on to the opposite side 
of H.P.C valve-casing, and from above downwards, 
passing from the edge of one flange to the lower 
edge of the other. Fit on a small plate of sheet 
brass, to close up the space between the cylinders, 
both above and below, attach these plates to the 
upper and under surfaces of the lagging by screws, 
and fill the interior of this space with plenty of 
horse-hair, as this is a bad conductor of heat. The 
lagging is kept in position by two brass bands 
passing round it, one near the top, and the other 
near the bottom of each cylinder; these can be 



COMPOUND MARINE ENGINES. 289 

fastened by pins or solder at their ends. The 

lagging will tend to keep the cylinders hot, and 

give a neat appearance to the engine when finished. 

The connecting-rods are of iron, with the big ends 

of brass (see page 97) ; they are forked at the small 

ends, so as to embrace the cross-head pin. The forks 

may be cut out of the solid end, which is left thick. 

The cross-heads are of brass, or iron, screwed to 

the piston-rods, and these slide simply between 

the flat sides or guide-surfaces of the standards. 

A disc of iron, or brass, is fixed by a set-screw 

at one end of the crank-shaft, having four holes 

drilled through it near the circumference, for bolts 

to pass through, and join it to a similar disc on the 

end of the propeller-shaft. If the disc is made 

heavy, it will act the part of a balance wheel or 

fly-wheel, and save putting one on. The screw 

propeller can be purchased ready made, and mounted 

on a turned shaft, the same size as the crank-shaft ; 

the propeller may be keyed on, or fixed by means 

of a set-screw. The length of this shaft will depend 

Dn the size of the boat in which the engines are to 

be placed. This shaft is coupled to the crank-shaft 

u 






290 MODEL ENGINE CONSTRUCTION. 

by means of bolts, passing through both discs, as 
mentioned above. The propeller-shaft must pass 
through a long stuffing-box, which goes through 
the stern of the boat, so that no water can get 
access along the shaft to the engines. 

The dimensions of this engine will be got by 
referring to the working drawings, but the amateur 
will require to make special patterns to obtain 
castings. The patterns must all be made a little 
larger than the finished sizes, to allow of filing, and 
turning on the lathe. The L.P.C. steam-ports are 
A" x A" exhaust-port \" x T V', travel of slide-valve 
■J", slide-valve |"xj|". Sides of valve-casing are 
■J" thick, to allow of bolt-holes, top and bottom 
borders, each T y thick. The H.P.C. steam-ports 
are ^" x T y, exhaust-port \" x jV'> travel of slide- 
valve J", slide-valve i"x^J-". The top cylinder 
covers are both cast from the same pattern, 2%" 
diameter; these, as well as the cylinders, are made 
of brass or iron. The standards have guide-surfaces 
between the legs and the upper part; these can 
be either of brass or iron. The bed-plate is a 
plate of iron, or brass, -fa" thick, having holes cast 



COMPOUND MARINE ENGINES. 291 

or slotted out for the crank and connecting-rod end 
to pass round when revolving. The two cylinders 
stand on their respective supports, quite indepen- 
dent of each other, being kept in place by bolts 
and nuts passing through the covers. They are 
joined together by the steam-pipe (with or with- 
out flanges) soldered on one side to the H.P.C, 
receiver, and to the valve-case of the L.P.C. on the 
other. For further information about attaching the 
cylinders to their front covers, boring and fitting 
the stuffing-boxes so as to get them in the central 
line of the cylinder bore, see pages 100 and 165. 

Action. — From the drawings, it will be apparent 
that the steam coming from the boiler is admitted 
by a cock, or stop-valve, through the pipe A to 
the valve-casing of the H.P.C. ; here it is controlled 
by the slide-valve, and after doing work in the 
H.P.C, it enters through the exhaust-pipe into 
the receiver B; from thence it passes to the L.P.C. 
by the pipe C, and after doing further work there, 
it exhausts direct into the atmosphere, through 
the exhaust-pipe D, fixed in the valve-casing of 
the L.P.C. 



292 MODEL ENGINE CONSTRUCTION. 

The compound tandem engine (see Sheet No. 20) 
is the form of engine used in all the White Star 
liners. This engine resembles the last one, but is 
of simpler construction, and can nearly be made 
from the same patterns. The cylinders are arranged 
in tandem fashion, so that the H.P.C. is placed 
on the top of the L.P.C., instead of side by side, 
and consequently both work upon the same crank- 
pin; the piston-rod and valve-spindle are common 
to both cylinders. This engine is much simpler 
to fit up than the last one, there being fewer 
parts, and only one crank on the axle; but the 
fitting up must be very carefully done, to* get 
the cylinders and steam-chests in line, to ensure 
success when working. There is no receiver sur- 
rounding the H.P.C, as both cylinders take steam 
at the same time, and it is led direct from the 
H.P.C. exhaust-pipe to the valve-chest of the 
L.P.C Patterns for a separate top and bottom 
cover for the H.P.C. must be made, the under 
one only having a stuffing-box and gland. The 
top and bottom covers, with the standards of the 
L.P.C, are cast from the same pattern as was 



COMPOUND MARINE ENGINES. 293 

used for the last engine. Both L.P.C. covers 
contain a stuffing-box and gland, as the piston-rod 
passes through the top cover, on its way to join 
the H.P.C. piston. The H.P.C. must be raised 
a good way above the L.P.C, in order to allow 
of room to unscrew the glands, and pack the 
piston-rods. This is accomplished by means of 
a special casting, a "distance piece," which sits 
upon the L.P.C. cover and supports the H.P.C, 
which rests upon it, and is attached by bolts to 
both cylinders. For dimensions, see Sheet No. 20, 
and how to construct patterns, see page 308. Get 
the distance piece cast in brass, with a bevelled 
hole through its interior. This casting must be 
mounted on a temporary wooden shaft, turned 
and faced in the lathe. The longitudinal slots in 
the sides can be drilled, and filed out to shape. 
The cored passage can be filed smooth with a 
round file, after which bolt-holes can be drilled 
through the flanges. This is better than casting 
the covers and distance-piece in one; for, being 
so small, it would be next to an impossibility 
to drill holes for the piston-rod, and fit the glands 



294 MODEL ENGINE CONSTRUCTION. 

correctly. One standard only is required, having 
the bottom cover of the L.P.C. cast upon it. The 
piston of the H.P.C. can be screwed on to the top 
of the rod, and a nut put on to secure it. The 
best way to attach the piston of the L.P.C. is to 
make it a tight fit upon the rod, drive it on, then 
braze, or use hard solder, and it will be quite firm. 
The valve-casing of the L.P.C. has two stuffing- 
boxes and glands ; the valve-spindle passes through 
a stuffing-box above and below, the spindle being 
common to both slide-valves. H.P.C. steam-ports 
are -g^' X T V'> exhaust-port \", travel of valve -J-" 
X T V", size of slide-valve i"x^f". L.P.C. steam- 
ports are -grV'x-rV" exhaust-port i"x T y, travel 
of valve J", size of slide-valve -§-" x Jf". 

The bed-plate is similar to the last, but contains 
only one slot. There are two bearings, of brass, 
one on each side of the standard. To fit these 
up, see page 165. There is no need of a weigh - 
bar to raise and lower the link by, but two lifting- 
links are pivoted direct to the reversing-lever 
working in the quadrant. There are two eccentrics, 
one for forward, and one for backward motion, 



COMPOUND MARINE ENGINES. 295 

and these control both slide-valves upon the one 
spindle. The eccentric-pulleys are put on the shaft 
outside the bearings, one end of the shaft carries 
a disc, as before. This engine could be fitted up 
without a link motion, and this will simplify 
matters very much. 

Action. — The steam enters the H.P.C. from the 
boiler by the pipe A, and after exhausting from 
this cylinder, passes through the pipe B to the 
L.P.C., and after doing further work there, it ex- 
hausts into the atmosphere through the pipe C. 
No receiver is required, as both cylinders are 
ready to receive steam at the same time, and 
consequently it passes direct from the H.P.C. 
to the L.P.C. Lagging may be put round both 
cylinders, or they may be left as they are repre- 
sented in the working drawings, without any. 



CHAPTER XII. 

PKOPOKTIONS OF ENGINES, ETC., PATTEKN-MAKING, 
CASTINGS, ETC. 

Proportions of Engines and Boilers. 

As a rule, if the boiler for any engine is made 
five times as large as the cylinder, it will be of 
sufficient size to steam well. 

To find the thickness of metal suitable for a boiler 
to stand a pressure of 15 to 16 lbs. per square inch 
(more than sufficient to run any stationary engine), 
divide the diameter of the boiler in inches by 100, 
this gives in decimals the thickness of metal suitable 
for the above pressures. 

A good and safe method to find out what pressure 
a model boiler will stand, is to fill it quite full of 
water, load the safety-valve twice as much as you 



PROPORTIONS OF ENGINES, ETC. 297 

intend to use, and light the fire; as the water 
heats, it expands, and either will lift the safety- 
valve or the boiler will quietly separate without 
an explosion : this is called the " cold method " of 
testing a boiler. A vertical brazed copper boiler, 
16" X 8" diameter, fire-box T X 8", with a 1£" central 
flue, if heated with a gas-burner (too small for coal 
or coke), will drive an engine with a cylinder 1" 
bore, 2" stroke, fly-wheel 5|", cut off at three- 
quarter stroke. 

In small boilers, to get sufficient draught of 
air through the furnace to make the fire burn, 
the horizontal flue-tube should always be at least 
1-J-" diameter (inside), and the funnel should never 
be less than from -§■" to f" diameter. These 
sizes are suitable for burning methylated spirits 
of wine, or very small blocks of wood steeped in 
paraffin oil or methylated spirits. Smaller tubes 
than this do not keep up steam, from shortness 
of draught. Charcoal and dry wood will burn 
well in a boiler with a flue of 1-J-" diameter, though 
there may be a little difficulty in getting the fire 
properly started. Common coal and coke require 



298 MODEL ENGINE CONSTRUCTION. 

a flue about 2" diameter, and a fire-box at least 
6" square. 

As considerable time and trouble has been spent 
on the working drawings, in order to get good pro- 
portioned engines, and models that will work well 
when made, we think that the sizes of boilers 
adopted, with the great amount of heating surface 
provided in each, and the quantity of wicks burn- 
ing in the fire-boxes, will prove satisfactory. 

Notes on Painting Engines. 

The cylinders of stationary engines require paint- 
ing, and these can be made of a green, or any 
other suitable colour, by using ordinary paint mixed 
with copal varnish. The covers and bed-plates 
ought to be polished bright all over, and not 
painted. The wooden stands may be stained, either 
a mahogany or rose-wood colour, according to taste, 
by using " Castle Brand's " staining fluid, and 
putting on three or four coats. The spokes and 
insides of fly-wheel rims may be painted. 

The locomotives. Before painting, remove all 



PATTERN-MAKING, CASTINGS, ETC. 299 

roughness from the outer surfaces with fine emery 
paper, and grease with naphtha. Afterwards begin 
painting the boiler and engine, using a coat of 
red lead as a basis. When this is dry, paint the 
boiler, frames, wheels, cab, cylinders, and tender a 
green colour, smoke-box and funnel black, inside of 
cab and tender vermilion, or other suitable colours. 
Give two or three coats of paint, then finish with 
black and white stripes. Always paint a boiler when 
it is warm (hot water should be poured inside 
before beginning to paint), as in this way paint 
adheres better, and is not so liable to blister and 
peel off, after steam has been got up once or twice. 
Mixing copal varnish with the paint before using 
it, saves trouble in laying on a coat of varnish after 
the painting is finished, and looks nearly as well. 
Of course the varnish need only be mixed with 
the third, or last coat of paint. 



Pattern-making and Castings. 

We should like to devote a long chapter to 
pattern-making, but want of sufficient practical 



300 MODEL ENGINE CONSTRUCTION. 

experience prevents our doing so ; however, we shall 
give one or two hints upon this subject. 

When going to make an engine, of whatever 
kind it may be, stationary, locomotive, or marine, 
prepare a drawing of the engine, make working 
drawings of the various parts, and mark off on these 
first the centre lines, in red ink, after which mark 
off from the centre line the dimensions of that part, 
so as to insure that it really is the centre line of 
that part. The drawings may be made full size, or 
to some convenient scale ; in any case, always put 
in the distance, or dimension lines, as trouble will 
be saved in getting the dimensions afterwards from 
the drawing, by applying a rule, or a suitable scale. 
When castings are required, and the amateur has 
decided to make them for himself, patterns must 
be made in wood from these working drawings, and 
it is best to make the patterns always a shade 
larger in all their dimensions, so as to allow for 
the castings being worked on the lathe, and made 
to the requisite size. For small engines, shrinkage 
of the castings may be ignored. Pine, deal, or 
mahogany, with straight grain, are perhaps about 



PATTERN-MAKING, CASTINGS, ETC. 301 

the best kind of wood for pattern-making. Always 
taper the parts slightly which enter deepest into the 
sand, as this allows them to be more easily with- 
drawn. Avoid sharp internal edges upon patterns, 
and join the parts together with glue, or small 
sprigs. After the patterns are finished, and smoothed 
over, they ought to be varnished, or better still, 
brushed with blacklead, as then better moulds can 
be made from them. For the engines illustrated 
in this work few patterns will be required, except 
for the fly-wheel, cylinder, valve-case, bed-plate, 
and bearings, all the rest of the parts (including 
the piston) can be made out of brass rod, brass wire, 
and sheet brass, and these can be purchased square 
or round, of the requisite size. The patterns for 
wheels, either drivers or fly-wheels, when small, 
are best cut out of solid wood. The wheel is first 
turned as a disc, and with a flange ; if a locomotive 
wheel, the boss is left wider than the rim; after 
turning, mark off the boss, the rim, and the spokes, 
lay the wheel on a hard piece of wood, and cut out 
the spaces between the spokes. Next reduce the 
spokes to the proper size and thickness, with a 



302 MODEL ENGINE CONSTRUCTION. 

sharp knife and a file, then file the parts, smoothe, 
and finish with sand-paper, coat over with black- 
lead, and the pattern is complete. Never drill a 
hole for the axle in the pattern, but do it after- 
wards in the casting. Wheel patterns have a 
tendency to become a little oval in time; still, if 
made of a diameter larger than what the finished 
wheel is to be, it will not matter much though the 
pattern does get a little oval. Another method is : 
soon after making the pattern, before it has had 
time to become oval, to get a casting from it, and 
use this metal pattern for all future wheels, as it 
does not change in any way. 

Note. — The small wheels should be cast in brass, 
or gun metal, which is much easier to work than 
iron. A good deal of trouble is saved in making 
the wheel-pattern, by having no more spokes than 
are absolutely necessary to render the wheel strong, 
and hold it together. Still, we do not advise fewer 
spokes than twelve in a locomotive driving-wheel, 
and perhaps six in a fly-wheel for a stationary 
engine. 

The cylinder pattern (see Fig. 58) must always 



PATTERN-MAKING, CASTINGS, ETC. 303 



be made a size larger in all its dimensions than 
the finished cylinder is to be, so that after the 
casting is turned on the lathe and completed, it 
may agree with the working drawings. 

It is easiest in these small cylinders to make a 






Fig. 58. — Patterns for making a cylinder. 

separate pattern for the steam-chest, cast it quite 
distinct from the cylinder, and bolt it on after- 
wards. For the body of the cylinder, take a piece 
of hard wood (chuck it between the lathe centres), 
sufficiently long to include the body A and the 



304 MODEL ENGINE CONSTRUCTION 

cores B at both ends. Turn the flanges, and the 
body as well as the cores; these last should be 
left about T V' less in diameter than the finished 
bore is to be. The cores enable the moulder to 
cast a cored-out passage through the cylinder. 
After removing the pattern from the lathe, the 
steam-chest block, with the valve-face, is neatly 
fitted to the curve of the cylinder, and glued on 
upon one side, and must run from one flange to 
the other. The exhaust-pipe is made and glued on 
as a block (C) only, instead of as a pipe ; the shape 
is apparent from the drawings. Brackets or feet 
(F) can be glued to the cylinder body inside the 
flanges, for resting on the bed-plate, or a flange 
can be glued round the valve-chest for bolting 
it to the side frames in a locomotive. D is the 
valve-case, in front of which a boss is glued on for 
the slide-valve stuffing-box. The cover E fits the 
outer side of the valve-case. The steam-pipe is 
simply a block, and not a pipe, glued upon the 
outside. Steam-ports are never drilled in patterns, 
but are made afterwards in the cylinder casting, 
in the way already mentioned. Separate patterns 



PATTERN-MAKING, CASTINGS, ETC. 305 

are made for the covers, which are simply discs. 

When making a locomotive, both cylinders should 

be cast from the same pattern. 

A pattern for a rail is made by sawing and 

planing a piece of straight grain yellow pine or 

box-wood to the following dimensions : 18" x §' ' X \". 

Lay the wood on a bench, one end of it resting 

against a support, take a -^"-groove plane (rest one 

side of the plane firmly against one side of the 

piece of wood, the opposite side of the wood being 

fixed against two nails driven into the bench to 

steady it), and cut out a longitudinal groove 

throughout the full length of the piece of wood to 

a depth of T V'. In order to keep the plane from 

grooving the wood too deeply, it may be necessary 

partially to block up the groove in the plane by a 

piece of wood driven a tight fit in between the sides 

at the bottom of this groove, to prevent the chisel 

in the plane cutting the groove any deeper than 

T V". Reverse the piece of wood, and plane a 

corresponding groove (leaning the plane laterally 

against the same side of the wood as before, though 

this is turned upside down) exactly opposite to, 

x 



306 MODEL ENGINE CONSTRUCTION. 

and cut to the same depth as the first groove. 
The piece of wood has now somewhat the shape 
of a rail, with a head and a heel and a central 
web, which should be left about -J-" thick. Take 
the pattern, and with a smoothing-plane remove 
all the superfluous wood equally on both sides 
above and below the web, so as to leave the head 
and heel each T V' thick and \" broad. All the 
corners should be rounded off with a smooth 
file, and not left sharp; both head and heel must 
be made slightly convex on their outer surfaces; 
in short, the rail must be made a correct model. 
Never drill bolt-holes for fish-plate bolts in the 
patterns; these can be drilled afterwards in. the 
castings, if required. After filing, polishing with 
sand-paper, and coating with blacklead, the pattern 
is ready for the foundry, and any number of rails 
can be cast from it, preferably in malleable iron, 
or Swedish steel. Sixteen rails will be required 
to lay a line 12 feet long. The drawings of the 
rail on Sheet No. 17 are full size. 

A pattern of a chair, or support that lies between 
the rail and sleepers, is given in Fig. 59. Make 



PATTERN-MAKING, CASTINGS, ETC. 307 

it the size of the drawing, having a slot through 
which the heel and web of the rails pass. The 
inner jaw rises upwards and curves inwards, so 
as to rest against the inner side of the web of 
the rail, and a wooden wedge is driven in between 
the outer jaw and the rail, to hold it in position 
when the chair is fastened to the sleeper. The 

4 

• 73 



_/iX_ 



( 1 1 1 m 



Fig. 59. — Elevation and Plan of Pattern for Chairs. 

central slot must be made smaller than it is to 
be in the casting, and may be made to the correct 
size in the latter to suit the rail by filing. Get 
all the chairs cast in brass. 

Both standards for the marine engine (page 284) 
are cast from the same pattern. The pattern is 
cut out of a wooden block to shape, and finished 
by filing and sand-paper. Cover it over with black- 
lead before sending it to the foundry ; sometimes it 



303 MODEL ENGINE CONSTRUCTION. 

is varnished instead. The flanges for bolting to 
the bed-plate by are made separately and attached 
by glue and sprigs. The bottom cylinder cover is 
fixed on at the top end. This is a separate pattern, 
turned to the proper size, and then fixed in position, 
with the centres truly in line. A special pattern 
for a "distance piece" (page 293) must be made 
according to drawings (see Sheet No. 20). The 
pattern is turned to a diameter rather larger than 
the dimensions given ; leave a core at both ends 
projecting beyond the flanges, tapered slightly to 
correspond with the taper which the cored-out 
passage through the interior of the casting must 
have. The longitudinal slots had best be drilled 
out afterwards in the casting. 

Tools required for pattern-making are a tenon 
saw, a small axe, a screw-driver, one or two sets 
of different-sized chisels and gouges, a small glue- 
pot, a pocket-knife, some few sheets of coarse and 
fine sand-paper, varnish, and blacklead, along with a 
set of wood-working tools for the lathe, comprising 
a set of chisels and gouges, which may be purchased 
in blocks. 






PATTERN-MAKING, CASTINGS, ETC. 303 

Castings for making good working engines can 
be had from any of the numerous model-makers, and 
without recommending the castings of any parti- 
cular maker, which we feel we are not in a position 
to do, as we have always made our own patterns, 
we will mention the names and addresses of one 
or two model-makers where good castings can be 
obtained — Mr. R. A. Lee, 203 Shaftesbury Avenue, 
London, W.C. ; Messrs. Butler Bros., 135 Bentham 
Road, South Hackney, London, E. ; Messrs. Lucas 

tnd Davies, 67 Farringdon Road, London, E.C. ; 
[essrs. Stiffin and Co., 51 Roding Road, Homerton, 

iondon, E. ; Mr. Bateman, 205 and 206 High Hol- 

>orn, London, E.C. Copper tube, sheet, and copper 
rivets can also be had from Messrs. Stanton Bros., 

f 3 Shoe Lane, London, E.C. 



CHAPTER XIII. 

HOT-AIR ENGINE, SMALL-POWER ENGINE, AND NOTES. 

A hot-air engine. This engine is easily made, is a 
very safe one — there being no boiler which might be 
liable to explode — and when once started it will 
work away for hours without any attention, if a 
small gas-jet or spirit-lamp is burned in the furnace, 
and a proper circulation of cold water is kept con- 
stantly flowing over the heater to keep the parts 
cool. The engine is composed of the following parts 
(see Sheet No. 21). A is the working cylinder 
(which contains a trunk piston) with an inlet-port, 
which by means of a pipe communicates with the 
heating cylinder B. There is no cock on this pipe, 
but one could be fitted on. The under surface of 
B is heated by a spirit-lamp burning inside the 
fire-box C, and the top of B is cooled by a 



HOT-AIB ENGINE. 311 

water-tight casing D, in and out of which a constant 
flow of cold water must pass. E is a compression 
piston, packed with asbestos twine ; the plunger-rod 
has screwed upon it (a short way above this piston) 
a small piston F, which is packed with tow. This 
fits and works in a small cylinder, which passes 
through the centre of the water-tight casing above 
the heater. The upper end of this piston-rod, after 
passing through the small cylinder, is slotted out, 
and pivoted by a bolt to a connecting-rod, the cross- 
head of which engages with the small centre crank 
on the fly-wheel shaft. This small crank leads the 
crank of the working cylinder by an angle of about 
80°. For dimensions, see the working drawings. 

The engine can be made from No. 18 sheet brass, 
except that the bottom of the heater should be of 
No. 18 sheet copper. The furnace is circular in 
shape, brazed together, and to the bottom of the 
heater, having a fire-door at one side. And from the 
opposite side a funnel comes out at right angles, 
and joins by an elbow-joint to the upright funnel. 

Rivet on a small hinged door, and also three feet, 
to raise the fire-box from the floor, and allow air to 



312 MODEL ENGINE CONSTRUCTION. 

enter to support combustion. The lamp is made of 
tin, of a circular shape, having one small central 
wick, \" diameter. There is a funnel to pour in 
methylated spirits by. The lamp sits inside the fire- 
box. All the joints of the funnel, the heater, and the 
water-casing should be brazed together, with the 
exception of the upper disc; this may be soldered 
on afterwards. The heating cylinder and water- 
tight casing should be in one piece; this forms a 
cylinder with a brazed longitudinal seam. A circular 
copper disc is fitted and then brazed inside near the 
middle, to divide this cylinder into two equal parts, 
the heater and the water-casing. Another disc 
should be brazed or soldered to one end, that which 
forms the top of the water-casing. The free end of 
the cylinder is afterwards to be brazed to the top of 
the fire-box, a disc being fixed between them. The 
centres of the upper and middle discs must be 
marked and drilled before fixing them in their 
places, and afterwards these holes can be widened 
to the proper sizes to allow the small cylinder G 
to be pushed through them both, the ends of which 
are then soldered to the discs (that to the bottom 



HOT-AIB ENGINE. 313 

disc must be fixed before the fire-box is attached). 
A piston must be turned to fit this cylinder accur- 
ately; this piston is screwed on to a rod coming 
from the compression piston ; the lower end of this 
rod has brazed upon it two copper discs, at a dis- 
tance of about 1" apart. The space between them 
is packed by rolling asbestos twine round the rod 
until it is filled with it, and the twine is flush with 
the edges of the piston. The two discs attached 
to the rod, with the packing, constitute the com- 
pression piston. The upper end of this piston-rod, 
after it passes through the small piston, is slotted 
out and pivoted to a connecting-rod, which engages 
with the centre crank. Having now finished all the 
parts, we take the compression piston in one hand, 
and the heating cylinder with water-casing in the 
other (the fire-box not yet being attached). From 
the lower end push the piston-rod of the compres- 
sion piston through the central vertical cylinder, 
until the small piston enters it, when it will be 
found, if the correct distance is observed between 
the two pistons, that when the upper one enters 
the cylinder, the compression piston just enters the 



314 MODEL ENGINE CONSTRUCTION. 

heater. The heater must now be brazed by its 
free end to the top of the fire-box, a copper disc 
being fixed between them. 

Connection must be made by means of T V' pipes 
with the water-tank, and the casing D, in order to 
provide a constant circulation of cold water. The 
working or power cylinder is a brass casting, bored 
out on the lathe, the same way as a steam cylinder ; 
it is open at the upper end, and has one port only 
at the foot. It is fixed vertically to and communi- 
cates by the port with the interior of the heater. 
A bottom cover can be cast on, or attached by studs. 
The pipe from the heater to the cylinder is T V' bore ; 
this can be screwed into the cylinder, and soldered 
to the heater. The cylinder should be surrounded 
by a water-jacket made of sheet brass, communi- 
cating at the top with the cold-water cylinder over 
the heater, and underneath having a cock to let out 
water by. A trunk piston — i.e. a piston hollowed 
out in its interior (see working drawings), with a 
short piece of brass screwed to its centre, which is 
drilled and slotted out to pivot to a connecting-rod 
• — is fitted in the working cylinder, and is attached 



HOT-AIE ENGINE. 315 

direct to the connecting-rod, which engages with 
the crank on the end of the fly-wheel shaft. The 
crank-axle can be \" diameter, turned to a little 
less at the journals. It can be purchased ready- 
made, of solid steel, with a -}■" throw, in which case 
an end crank must be fixed on upon one side, 
suitable for a H" stroke, and set so that there is 
80° degrees between it and the other crank. Or 
the crank might be a built-up one, with the webs 
of brass screwed and soldered together (see pages 
105 and 285). The shaft revolves in bearings, sup- 
ported on pillars fixed to the top of the circulating 
tank. 

The water-tank is made of tin plate, or sheet 
brass, bent into a circular shape, and soldered to- 
gether, with a flat bottom. The mouth is open, for 
pouring in a fresh supply of water now and again. 
Fix the tank as near the engine as possible. Con- 
nection is made from this tank to the circulating 
tank over the heater by two T V' bore brass pipes, 
and a better circulation of water is kept up by con- 
necting the tube from the bottom of the engine tank 
with the top of the circulating tank, and vice versa. 



316 MODEL ENGINE CONSTRUCTION. 

The water is also allowed to circulate from the 
circulating tank round the power cylinder inside 
the water-jacket, from whence it can be let out 
by a cock; or if this cock is kept slightly open, 
water will continue to circulate. There is also a 
cock entering the circulating tank near the foot, 
which is used to draw off the water over the heater 
when this begins to warm, and allows fresh water 
to take its place. The fly-wheel may be either of 
brass or iron, and as so few castings are required 
for a hot-air engine, we think the amateur will 
be able to make all these from his own patterns. 

Directions for working. Fill the tank quite full 
of cold water, pour spirits of wine into the spirit- 
tank, and light the fire; oil the motion, especially 
the working piston. In a few minutes, on giving 
the wheel a turn or two by hand, it will begin to 
revolve, and will continue doing so as long as a 
proper circulation of cold water is kept up, and 
the spirit kept burning in the fire-box. 

The action seems to be explained as follows. The 
compression piston first compresses the cold air into 
the lower part of the heater when descending, where, 



SMALL-POWER ENGINE. 317 

on being heated, a greater increase of pressure occurs, 
corresponding to the increase of temperature, and 
this impels the working or power piston up to the 
end of its stroke. The compression piston having 
now moved upwards, transports the air alternately 
from one end of the cylinder to the other, and 
here it is cooled by the water-tank, and restored 
to atmospheric pressure, the pressure falling to a 
minimum, and then the power piston descends 
and completes the stroke, when compression again 
begins, ready for the second stroke, and so on. 

Note. — If a leak occurs anywhere, this spoils the 
efficiency of the engine. If the water over the 
heater gets too hot, the engine stops, as the con- 
tained air can no longer be expanded and contracted 
as before. 

This engine makes a powerful working model, 
but an engine half the size of the working drawings 
will work fairly well. Working hot-air engines can 
be purchased from Mr. Seal, 67 Carthew Road, 
Hammersmith, and vary in price according to size 
and finish from 12s. 6d. up to 26s. 

Small-power engines. We meanwhile leave these 



318 MODEL ENGINE CONSTRUCTION. 

engines out of account, but have no hesitation in 
saying that the amateur who has successfully made 
any of the models mentioned here, may safely take 
in hand to make a small-power engine, suitable for 
driving his lathe, from a set of castings as supplied 

by the model-makers. If the cylinder is bored 

I 

before the castings are sent out, the engine will 

be easily made. This had best be done, for the 
cylinder requires very careful workmanship. A 
suitable boiler, with all fittings, should be purchased 
ready-made. We do not advise any one to attempt 
small-power boiler-making at home, as the result 
can hardly be anything but disappointing, and 
probably disastrous. An engineer, or even a boiler- 
maker, can do very little work at home, consisting 
merely of riveting up, and attaching fittings and 
mountings. Rolls are required for bending the 
plates, a furnace for heating, and a templet-block for 
flanging the crowns, the cross-tube, and for welding 
up, and this can only be done successfully in an 
engineering workshop. 



NOTES. 319 



NOTES. 

When water boils (at a temperature of 212° 
Fahr.) a vapour is given off which is called steam. 
This possesses, like other gases, two properties, viz. 
expansibility and elasticity, along with another, 
condensability, all of which render it of value in 
imparting motion to a steam-engine. 

Expansibility. This property can be shown by 
purchasing one or two small glass candle bombs, 
which contain water, and when one of them is 
stuck by its narrow end into the top of a tallow 
candle at the side of the wick and lighted, in a 
short time it explodes with a report into innumer- 
able fragments. This result is caused by steam 
at atmospheric pressure occupying 1642 times the 
volume of its weight of water, or, in other words : 
water occupying the space of a cubic inch when 
converted into steam will occupy the space of a 
cubic foot ; and suppose the bomb held the above 
amount of water, consequently, when this water 
becomes steam there is no room for it in the ' bomb, 



320 MODEL ENGINE CONSTRUCTION. 

and the pressure increases till it shatters the bomb 
all to pieces. 

Condensability. This is the property which steam 
possesses of returning to water when the heat is 
suddenly withdrawn, and a lowering of temperature 
takes place. Advantage was taken of this fact in 
the early forms of the Newcomen atmospheric beam 
engine, where the weight of the beam raised the 
piston to the top of the cylinder, and by suitable 
arrangements the steam space below the piston was 
then filled with steam, which was suddenly con- 
densed by a jet of cold water. This setting up a 
vacuum, caused the piston to descend, as it was 
forced down by atmospheric pressure, and so com- 
pleted the stroke. 

Elasticity. This is the property steam possesses 
of having the power of resistance to external 
pressure, and the steam which is formed at 212° 
Fahr. possesses just that degree of elastic force 
which is required to balance and resist the pressure 
of the atmosphere. At 212° Fahr. its elastic force 
just equals one atmosphere, or 14*7 lbs. per square 
inch. This property, and the previous one men- 



NOTES. 321 

tioned above, can be easily shown by Wollaston's 
apparatus, which consists of a bulb and glass tube 
provided with a piston and hollow piston-rod work- 
ing freely through a cork. On filling the bulb with 
water and heating it, so long as the cock communi- 
cating with the piston-rod remains open, there is an 
escape of steam ; on closing the cock, steam forces 
the piston upwards, subsequent cooling causes con- 
densation of the steam, and the piston descends by 
atmospheric pressure to its former position. 

Saturated steam is steam in contact with the 
water from which it is generated. This is the 
condition in which it is usually supplied to engines. 

Super-heated steam is steam absolutely dry, and 
with no vapoury particles held in suspension; its 
temperature is also higher than that due to the 
corresponding pressure of saturated steam. 
Horse-power of an engine. 

Energy is the capability of doing work, and this 
is measured by the number of units of work done. 
Power is the rate of working, or the work done in 
unit time ; so, according to engineers, the unit of 
work is the foot pound, and the unit of power is 

Y 



322 MODEL ENGINE CONSTEUCTION. 

called a horse-power (H.P.), which is the power of 
doing 33,000 foot pounds of work per minute. 
The horse-power is calculated as follows : — 
Let A equal the area of the piston in square 
inches, P the pressure in lbs. per square inch of 
steam, L the length of stroke in feet per minute, 
and N the number of revolutions per minute, then 

AxPxLxN -196350 x 30 x -083x400 

33,000 ~ 33,000 ~ uoy xx%r ' 

An engine with a cylinder of -J" bore and 1" stroke, 
working at 30 lbs. pressure, and making 200 revolu- 
tions per minute (by our calculation), will develop 
about T Vt/h H.P. ; if the mean pressure of steam 
was taken, and allowance made for friction, probably 
it would not amount to -g^cl H.P. 

In a model locomotive, steam of a greater pressure 
than about two atmospheres, or 30 lbs. per square 
inch, cannot be well maintained, hence it is advisable 
never to make the locomotive of too heavy material, 
but have it sufficiently strong only to be consistent 
with durability, and then it will give the best results 
when running upon rails. 



INDEX. 



Action of steam in cylinder, 154 

Adjusting eccentrics and setting 
slide-valve, 124 

Air, hot, engine, 310 

Beam engine, 157 

Bed-plate, 78 

Bell-chuck, 10 

Bench, lathe, 3 

Blower, 71 

Blow-off cock, 66 

Boiler fittings, 53 
,, horizontal, 31 
,, locomotive, 37, 46 
,, vertical, 48 

Broaches, 18 

Burnishers, 20 

Callipers, 21 

Carriages, railway, 253 

Carrier, lathe, 9 

Castings, 309 

Centre punch, 17 

Chisels, 15, 21 

Chucks, 8 

Clack-valve, 68 

Compasses, 22 

Compound marine engine, 281 

Condensation of steam, 320 

Connecting-rod, 97 

Covers, to fasten on, 87 

Crank-axle, 103 

Cross-head, 96 

Cutter, rose, 13 

Cylinder, 79 

,, covers, 84 
,, pattern, 303 
,, ports, 82 

Details of valve-gear, 139 

Directions for working locomo- 
tives and stationary engines, 244 

Distribution of steam in cylin- 
ders, 154 

Dog, lathe, 11 

Drill-chuck, 9 ; drill-points, 28 



Drilling metal, 12 

Drills, 27 

,, to temper, 26 

Eccentric-rod, 110 
,, straps, 110 
pulley, 112 

Elasticity of steam, 320 

Engine and boiler proportions, 29 6 
,, beam, 157 
,, bogie-tank, 231 
,, compound marine, 281 
,, fitting up an, 124 
,, horizontal, 161 
,, hot-air, 310 
,, locomotive, 200, 231 
,, portable, 189 
,, semi-portable, 194 
,, single locomotive, 236 
,, six- wheel tank, 241 
,, small-power, 317 
,, the steam, 78 
,, traction, 168 
,, vertical, 163 
,, ,, inverted, 165 

Expansibility of steam, 319 

Expansion- valve, 146 

Face-plate, 12 

Files, 16 

Finishing and testing engine 
under steam, 132 

Fly-wheel, 105 

Force-pump, 72 

Frame-saw, 21 

Fuel, 76 

Gauge-cocks, 65 

Glass water-gauge, 61 

Governor, Hartnell's, 149 
,, throttle, 119 

Grindstone, 21 

Guide-bars, 96 

Hartnell's governor, 149 

Horizontal boiler, 31; engine, 161 

Horse-power of an engine, 321 



324 



INDEX. 



Hot-air engine, 310 

Injector, the steam, 74 

Iron block, 21 

Joy's valve-gear, 152 

Lacquering, 22 

Lagged cylinder, 91 

Lathe-bench, 3 
,, carrier, 9 

Lifting-links, 143 

Link motion, 135 

Locomotive, bogie-tank, 231 
„ boiler, 37, 46 

,, single, 236, 239 

,, six- wheel tank, 241 

,, with tender, 200 

Loose eccentric, 134 

Marine engines, 281 

Metal shears, 22 

Metals, 25 

Method of soldering, 24 

Model-makers, 309 

Notes on painting, 299 
,, ,, steam, 319 

Nut, to make a, 19 

Oil-cups, 118 

Oil-stone, 21 

Packing piston and slide-valve 
glands, 248 

Painting engine and boilers, 298 

Parallel motion, 159 

Pattern-making and castings, 299 

Pattern-making, tools for, 308 

Pet- cocks, 90 

Piston, 91 
,, rings, 93 
,, rod, 95 

Pliers, 20 

Plummer block and bearings, 100 

Portable engine, 189 

Ports, steam, 82 

Pressure -gauge, 59 

Proportions of engines and 
boilers, 296 

Pump, force, 71 

Rail, pattern of, 305 

Railway, 264 

,, carriages, 253 



Railway chair, 276 

,, signal, 277 
Regulator, 43, 212 
Reversing-gear, 133 
,, lever, 144 
Rimers, 18 
Rose -cutter, 13 
Safety-valve, 53 
Screw, how to make a, 18 

,, plate and taps, 18 
Semi-portable engine, 194 
Setting slide-valve, 124 
Signal, railway, 277 
Slide-valve, 107 

,, ,, spindle, 110 
Small-power engine, 317 
Soldering bolts, 23 

,, method of, 24 
Spirit-lamp, 51 
Steam, condensability of, 320 

,, elasticity of, 320 

,, expansibility of, 319 

,, chest, 89 

,, engine, the, 78 
Surface-plate, 17 
Tandem marine engine, 292 
Taps and screw-plate, 18 
Tempering drills, 26 
Tender, 221 

Testing engine under steam, 132 
Throttle- valve governor, 119 
Tools for engine-making, 3 

,, ,, pattern-making, 309 
Traction engine, 168 
Valve-gear details, 139 

,, Joy's, 152 
Van, railway, 261 
Vertical boiler, 46 
,, engine, 163 
,, ,, inverted, 165 

Vices, 16 

Wagon, railway, 263 
Water-gauge, 61 
Wheel-valve, 70 
Whistle, 67 
Wood-chuck, 8 
Workshop, 29 






/ 



made to double 
>se appended. 



J 




Seclioivof foiternaL Fireboje 
showi7i^ sides arid circtilartop. 



V ; 



Locomotive Boiler. — Sheet No. 1. 




This boiler can also be Imade to double 
the dimensions of those appended. 



Elevation of Boiler. 





Cross Seclwn. through. Falf transverse. Jfatf frantr 
-Lamp and. Ergine frame Section- Elevation. 

Through the SmokeEoJe. 



Bjoirit Lamp. 




Ealf ' IV-ansverse. 

SertioTt- 

ThroughfOcXo^ 




J*erspective viewof the-internalFireBax, 



\ 




S eelion. of internal Firehox 
showing sides and circular top. 



^ 



v> 



' I I II 3D- 



L 



1. 



h £#- -*- /%) 




/bdiAm,?* 



Lamp elevation & Plaro* 
~£~Fit/l$ize. 



Veetical Boiler. — Sheet No. 2 



-H 



=te 



-U 



Vertical boiler, 
tyiludinal Half 

section. . elevation. 

* Full. size. 



• 






J-S- 



-ZM- - 



5 



Section of internal firebox . 




Full size . 
Plan of above 



V* 



-*l 



_1. 



h ££--*-/%) 




/ddioml 



Lump elevation & Plan,. 
~i~ fidl sine . 



f 



> 








T 



;- 



Beam Engine. — Sheet No. 3. 




E leva lion of enff ?e 



Y~-&& ---n 





_____ JE=fe 

" 7^ " 



/7am 






r 



vi|ap 



*■ — ^ 

Levers 1o move s Ude valve spindle. 

A, Vertical rod. B, Bell-crank. 







-h 



&IZONTAL E] 




back of Eny ate 



' 



•V 



Horizontal E: ie.— Sheet No. 4. 





W-h 



Ei Ivicw from /he back of £tujutc 









glare* 



]_-£J i— 



Bearings. 

Full size. 




rr 



HORIZONl 
< 



T 



* ^ : 

A- -2, 



^UT 



? 



r 




6 



L_JL 



Horizontal Engine. — Sheet No 5. 





kto.' 






L._ 



E 







— ^ 




I. 7. 



CQU 





E 



i — 



Perspective View. 






Inverted Vertical Engine. — Sheet No. 7. 





U3 



Perspective View. 



Elevation HfPlan 



1 




.. . 


- 


' - 


r . 






1 




1, 


s 






sdeejo. 



T 



Bach of Tender 
with. Spirit Lamp 




Box cover 



■ — 6k- 
Elevaiion, of Traction Engine-. 




Transverse Sectidn, behind fire box 



$srt of Engine- showing gearing 8c 
hove cover over both, wheels. 



i 



1 » ' A* 

V Z£ f' 81 

The Tender with lamp 
partly pushed in,' under 




Bach of Tender 
with. Spirit Lamp 



/ 



: 



Traction Engine. — Sheet No. 8, B. 



jl Slot bkf>. 



B 



± — . 



ti 



z£ 



lifting links 
-SlotUnk, 



I. Slot link-raised by one- end 
with double lifting links. 







!*-_*-- Jvi-ffl- -A-&-J 




\Slotlink- 
Zifangunks. 



k — _.__ 



~ **-._ 







Clutch for throwing upper jrinibninto gear. 
P. 'Jtnionwithboss . F.Fork, Fl.Ftdcrunu 
P. R. Pivoted ring , H.L.Mand-lever. 
S. Slotinboss of ^pinion-. 
B.Tiwtohold lever fixedin-fbrk. 



2 . Slot link raised by the. centre 
wiih dpvdile. lifting links. 



Slot link, 

gifting link. 




\ I 



^ 



3.Slot link raised hythe. ceAtrc 
with a single lifting link only. 



Flan-. 



Wedge bar. 





Elevation & Section- of kind- roadwkeel 

\- 
i 

_!_ 



Flevaiion Sc Section-off fading wheeh 




m 

lli 



!*tK 



If ie- .Brake. 
A.BraFhels.B.Bvalterod. C. Pivotnut. 
D.Lever. £. Strap going roundpulley F. 
& artUlched. t-o fulcrum &. 



L 












-*■ 






■«>l 



_J__ 



1 



ffatf- eruL 
Elevation . 




- ia£— * 



2Z#Z£ Irarthvers e< 

Section, through 

fire boa&. 



w 



o 
oo 

o 







~f~ L 



i Viy "»: |- 



-J-*4-4- 

i v" ! 



.4 >|" 



„A_ 



-/*-n 



■&*-*■- -*i— 



LongitcuHnaL section, of Boiler. 



~ -^-ft " 



"V" 






4 

i 

i 



._L_ 



Half- end. 
Elevation . 




Half- trari&vers e 

Section, through 

fire hoae. 



r 



\t 



<N( 



i 



ri 



Portable 



)'STh7Ce> 

A. 



r 




i 
i 

w.sr 

I 
I 




Elevation, of Portable Engine. 

8" 4 ,1 



i 

.MS. 






L 



I 

I 

-^- r 

-3f& 



-f-f- 

±1 
IT 

__l 

I 



J i 



£origitudinal section, of boiler. 






Half- end- 
elevation^. 






kJ 



t No. 11, A. 



# 




M 



iS. 







VZ 




Section I 
Steam 



Locomotive and Tender.— Sheet No. 11, A. 




Elevation. . 



--.si - 




1 y la/t of Locomotive 



Section through, Seclionthroiyk SeclionUiroitflv Section UipouaA 
Steampip*. txhaustpipc, #&&»*&&. firebox. 



B. 



\ 
\ 



■i 



Rev. 



k=r 



t 



Cyl 7 :? iicUa,nvV.. 
/" STroTco. 



Locomotive and Tender.— Sheet No. 11. B. 







Splasher. 



V 




Over hariqinq frames . 


1 

i 


t 
1 

1 




„ i 


„ i 


/i'-L ' * 


r -^-t- j 






1 «• 

r t n " * 

1 — * — 
i i 


1 

1 

! 


i 
i 


: i : 






«• 1 _ T. ^7e 




i 


1 


i 


i 




Flan of footplate % side frames. 



\BVtS >o{o 




I « 



J.-£J 



~#.A# 



/"&/7 <£ Elevation of bogie frame. 




Buffer. 



Side <K front viewofregulalorvocA.. 



Crank Put, 




Full size.. 



full size.. 
Loco, spring. 



%= 



4vs> ——. 



"*] 



^* ---©)- 



Coupling rod. 



.. 









. 



I 



Semi- Portable Engine.— JSheet No. 10. 



This engine can also be made to double the 
those 




Elevation Sjplan of Saddle. plate. 



H 

i 

Longitudinal e< ation %plan of Engine 



h— te- 




*e 



full Size?. 



Locomotive Engine and Tender.— Sheet No. 11, C. 



h- — zk~* 




\*- — 



Frame Plalc- 



Hand brake for Tender. Elevation $ Plan. 







r— hn 


1 








\ "4 


t 


k- - - -&£- -* — £-> 


.. 1 


JZ fclMcfrfwIdtrs 


I 


~7\\ 


O O OIO O O 
J__i^J 

O O OiO o o 


^ 







y^- 



Elevation &Plan of Lamp. 




Zoco. link motion.. 






■l 




i 

& 1 



^-=-3 



"1 



Bogie-Tank Locomotive.— Sheet No. 12, 



Mb-* 



HmnerforbrakeUocTc. 

-fhr 




Elevation, Zfplaw of frames . 



Elevation % plan of Bogie truck 



1 



I 






-Shek 



LL 



N> 



t 






1 



• 



Single Locomotive.— Sheet No. 13. 




-<3t£ -f *K £"# 

Elevation, of Locomotive. 



■*vv» 






>!^ 



'"SLif* JE 



£-1—3 f 



/2rA« 4v,/ 



r^t 



Elevation- of frames. 








jPZ«k, of -frames. 



*■$. 



%P 



/£-+- 






H 



LJ 



&- 



-^j — 3i 






27ns locomotive can also he mi 

«7te dimensions of those appended. 



1 






_i 






Longiluduuit. .ieMivriuf Boiler. 




Half end elevation W transverse Section. 
U\rotigk.Fa(iBaje. 



v 






1 



■ 



/ 



Six-Coupled Tank Locomotive. — Sheet No. 14. 




"W:: 




i 



OjZ, *1< Ka 



-/A 

/4- - 












U L 



*NS 



^ *fc~ 



4 

ll 



Eccentric fi.odarulfiiU.ey. Full Size. 



rrfrt = 
■a 



-i — p*°] p^ 






J 



Connecting Rod. Full Size* 



_L_L 



■T 






Elevation, and Plan, of frames . 





Roof of ' Engine, Cab. 



I I 

Half Front View. Front of Boiler 

Smoke Box. 
being removed.. 



n 



Railway Carriage. — Sheet No. 15. 

\ 




wm 



4r 



n 



A 



~s 



J-i" 



Half encLelevatums, 



Elevation* of carriage . 




.^wi^^^^^^i^w^^ 




t: iK^ifp 




_ /yy 




._]_ 



/*&«, o/ 7 carriage ■. 



.?&. ^ 



W 




jfi/aZ rwrr of foot boards Zjuuiger. 



Pers sTieicJi 
of fool* loai-ds & Juoig 



D 


<- -/£-> 


■i* 



-I* 



E0\* 



J_ 



#«e oftlie sides of a- 
comparimerilwitJvdoortvay: 



Adoorvritfi, 
ifiehing&titachuL- 



!« — //^ 



.--J 



■4 



~8~FulLsize~ 
TlijRrpqfofthc carriage 
fhe.7ongitadznaZ7ines s1i£>w 
tne- 3fflvcvts , made, zk the. wooc 7 - 
before- steaming ti^to gettbfo bendL. 




A Sheet brass hearing. 
& Aaele- box solderedoatside-. 
G Spring composedof plates of 
sheet Brass surroundecLby a. strap . 



•I 



~r 






> 
M 



T*-7f - " 



Railway Van. — Sheet No. 16. 




/^ 



JZlevaiioJi of Van 




Salfend elevation, 
Showing attachment 
of brahe, lever fyrod. 



C 

Fall size-. 
Chains for coupling the 
carriages together. 
A. Pin- hent ovaL. 
B PirvTnirms 7uaxZ£(j}ouub. 
C.ThJZ complete Units attached 
to form a. cham theendsofeaclv 
pin heiruf soldered after the links 
are, ■fhstenedtogethcr. 




Elevaiion. of a waggons. 






,1 




vssing 
mg rails. 




otTiis. 





bints setright for the main 7ine. 




oints , set right for siding or diverging line . 



Gmne-cfimg T?odi 




*7hintTWJl> 



Cross SectiojvofcLjpair of points Si. 
I sCocfc rails . 



Railway. — Sheet No 17. 

P n n 




flan, of a. Railway crossing 
A Guard-rails , Br^Wing rails. 



Contractors rails Sc points . 



W^_ 



Railway gauge-, < -made- of sheet brass) 
Used wlieusetting out a railway to gauge ihehnc 
A. Surface that rests on-top of rail. 
B .Riece ihatpassesdown-betweenih&raUs. 
die ends of this rub outhe inside oftheraxls 
w/ien f/iese- arcproperly gauged. 




r 



a. 





Top of SignaZJPostt. 




Lever & OuodrajiL 




si^r Signal 
lecture view* 



Mi-- 



S "«&• 



£ 



Ji 






1*1 



Railway Signal. — Sheet No. 18. 



Slot/i) 



A 



A 



T^p <?/" Signed- Post{. 




4tO f _/ *~* 



Side, of Signal Post- Back, of Signnl-Fbst. 




i '* 
Lever & Quadrant. 



Railway Signal 
jperspectivc- view. 



Maeinb Engines. — Sheet No. 19. 




.1 

J I 

f-|> ^ Brass block out ot whicJv the Crank 

■5t i$tobema.de.thewebsareslottedoui 




ThcBlock fitted into sha 
but Crank pin notyetcu* : 



Crank finished and 
Crank pin turned. 




Crank- complete, willi (tie 
Axle screwedinto thewel 



Head of bolt. 



Eccentric pidley divided into two halves for 
the purpose of ^getting it over die Aac/e. 



3zi 



TIC 



I 
r 



Nee 

I 






t ' sTfc,— h f~ 



r 



Plan of bedplate. . 



/ 



LIBRARY OF CONGRESS 



029 822 405 7 




Sttli 



N 



I nil 
ll 



i 



